Starter Troubleshooting

[whaNcock]

I have a 1950 8N 12V conversion with a front-mounted distributor. After sitting for two months, I tried starting my tractor (which had started and ran fine two months ago), and after 5-6 separate cranks of the engine, it finally started but ran very rough.

My first thought was water in the gas because I had forgotten to top the tank off and it was maybe 1/5 full. (Yes, I normally close the gas filter valve and had done so previous to this start.) I removed the glass bowl filter drained the gas out of the hole in the bottom of the tank and put new gas in the tank. Unfortunately, my battery was DOA upon trying to restart, so I replaced it with a new one. No big deal so far.

With the new battery and clean connections at the battery, the motor doesn"t crank when I press the start button, although I do hear the solenoid click and hear a "buzzing" noise. (It sounded like the buzzing was coming from the solenoid.) I"ve sanded and wire brushed all battery connections and the ground connection on the frame.

Per the Owner"s Manual troubleshooting guide, I took the wire off the positive terminal of the battery leading to the starter solenoid and touched it to the opposite post on the solenoid. It sparked, but nothing else happened. (See pic)

I"m guessing the next thing to do is take off the starter motor and clean the connection between it and the frame to ensure a good circuit for the starter. I"ve never done that before, so I want to check with the forum prior to taking the plunge. Is there anything else I should check first?

Thanks.

 

[JMOR]

I see tape on that battery cable......that may be covering a corroded cable/connector junction. Check them all (4) or try paralleling with your jumper cables.

 

[TheOldHokie]

(quoted from post at 18:33:58 12/07/11) I have a 1950 8N 12V conversion with a front-mounted distributor. After sitting for two months, I tried starting my tractor (which had started and ran fine two months ago), and after 5-6 separate cranks of the engine, it finally started but ran very rough.

My first thought was water in the gas because I had forgotten to top the tank off and it was maybe 1/5 full. (Yes, I normally close the gas filter valve and had done so previous to this start.) I removed the glass bowl filter drained the gas out of the hole in the bottom of the tank and put new gas in the tank. Unfortunately, my battery was DOA upon trying to restart, so I replaced it with a new one. No big deal so far.

With the new battery and clean connections at the battery, the motor doesn"t crank when I press the start button, although I do hear the solenoid click and hear a "buzzing" noise. (It sounded like the buzzing was coming from the solenoid.) I"ve sanded and wire brushed all battery connections and the ground connection on the frame.

Per the Owner"s Manual troubleshooting guide, I took the wire off the positive terminal of the battery leading to the starter solenoid and touched it to the opposite post on the solenoid. It sparked, but nothing else happened. (See pic)

I"m guessing the next thing to do is take off the starter motor and clean the connection between it and the frame to ensure a good circuit for the starter. I"ve never done that before, so I want to check with the forum prior to taking the plunge. Is there anything else I should check first?

Thanks.

Sounds like low battery voltage. Did you check it with a voltmeter? That should be number 1 on your list. You can also directly ground the starter with a jumper cable attached to the (-) post on the battery and the barrel of the starter. Then retry your solenoid bypass. If the starter still doesn't crank it's either battery or starter.

TOH

 

[Bruce (VA)]

You've got the right idea.

The solenoid is making a noise because of low voltage. That is likely caused by:

1. A weak battery (charge it & check it per tip # 49))
2. Dirty grounds/connections (remove the cables & clean the connections)
3. Bad cables or incorrect sized cables, as JMOR said (replace them - see tip # 41)
4. Bad ground between the starter & the block. (pull the starter away from the block & clean the mating area - see tip # 36)
50 Tips

 

[old]

Before I would take the starter loose I would use a jump cable and try to do the same thing as you did with the battery cable and see what happens. Your cable in the picture looks like it might not be very good as JMOR said also and it could be a very simple bad battery cable which you can not see but they sure will cause you big problems and removing the starter is not a fun thing to do either

 

[whaNcock]

First, thank you for the quick responses to my question. FYI, the voltage across the battery terminals reads 12.8V. I obtain the same reading when touching the common lead of the volt-meter to the tractor frame. This leads me to believe my battery's negative ground connection is good.

I did the jumper cable test and tested with a new battery cable to the positive terminal. Neither test caused the starter to function.

I first tried the jumper cable test by attaching the black wire to the negative battery post and the hood and the red wire to the positive battery post and two different terminals at the starter. (see pic #1) I sanded the posts so they showed bright copper prior to the test. As you can see in pic #2, the current was strong enough to burn two holes in the jumper cable clamp with a quick touch to the starter terminals. (one hole for each test) You can see the black mark on the left post in pic #1 from the test.

Secondly, I connected a new battery cable to the positive battery terminal as suggested by JMOR and made the usual connections. Upon pressing the start button, I heard the solenoid click very positively, but the starter did not function. However, the dust on the copper bar from the solenoid post to the starter post sure did vibrate when I pushed the start button! I assume that means my connections are good and probably indicates the mating surface between the block and starter is good too. I'm led to believe my problem is with the starter itself.

If removing the starter and having it tested at Advanced Auto is the next step, I'm having some trouble understanding Tip #36.

"If you need to remove the starter, always remember to have two nuts to place on the two long starter bolts as soon as you loosen them from the block. If you forget and the armature comes out of the starter housing, you will learn how to hold the spring-loaded brushes back with toothpicks while you put the armature back in the housing."

I'm thinking I screw the nuts on the long bolts after they come out of the block, but the tip says "as you loosen them from the block." I assume that means screw a nut on the block-end of the long bolt once it is free from the block itself. Maybe this should be obvious to me, but what size nut should I have for this? The bolt size is not listed in Master Parts Catalog with the exploded view of the starter.

Thanks again for all of your help. I'm new to working on tractors, and this forum is a life-saver.

 

[ZANE]

Try this. It will tell you if the starter is good or bad or something else like a bad battery etc.

When jump starting a 6 volt tractor with 12 volts it not necessary to hook the 12 volts to the 6 volts battery at all. As a matter of fact I strongly recommend against it.
Instead hook the 12 volts directly to the frame of the tractor for the ground and with the transmission in neutral and out of the way of the wheels of the tractor so you don't get run over touch the other cable from the 12 volt source to the post on the starter.
By doing it this way you don't even have to worry about the polarity of the batteries or which cable you have to ground or positive to the frame or the starter as the 6 volt system is not interred into at all with the 12 volts. Just turn on the switch and touch the hot cable to the starter post and it will go.


Zane
ZANES LIFT STUFF

 

[R Geiger]

"I'm thinking I screw the nuts on the long bolts after they come out of the block, but the tip says "as you loosen them from the block." I assume that means screw a nut on the block-end of the long bolt once it is free from the block itself"

You got the right idea! Not sure what the size is but you could take ONE all the way out and find the right size nut.

 

[whaNcock]

My tractor is a 12V conversion, so I have a 12V battery. It is also a negative ground configuration.

 

[whaNcock]

"I'm thinking I screw the nuts on the long bolts after they come out of the block, but the tip says "as you loosen them from the block." I assume that means screw a nut on the block-end of the long bolt once it is free from the block itself"

You got the right idea! Not sure what the size is but you could take ONE all the way out and find the right size nut.


What an easy solution! Thanks for the idea.

 

[Bruce (VA)]

" I first tried the jumper cable test by attaching the black wire to the negative battery post "

That's a very good way to blow up a battery. Didn't you read tip # 43? You do not have to be new to tractors to read & follow instructions. Do NOT ever hook up jumper cables to the battery posts.

" FYI, the voltage across the battery terminals reads 12.8V. I obtain the same reading when touching the common lead of the volt-meter to the tractor frame. This leads me to believe my battery's negative ground connection is good."

No, that doesn't tell you jack spit.

You have a low voltage problem most likely caused by poor connections. Remove all of the cables & clean every single ground. Both posts on the battery, the ends of both cables, the sheetmetal at the battery box, & the stud on the solenoid.

" However, the dust on the copper bar from the solenoid post to the starter post sure did vibrate when I pushed the start button! I assume that means my connections are good and probably indicates the mating surface between the block and starter is good too. "

No. It means you have a poor connection.

Loosen the starter bolts. Jiggle the starter some & it will pull away from the block. Then, put nuts on the bolts to keep the starter from coming apart. (tip # 36)
50 Tips

 

[whaNcock]

(quoted from post at 08:40:16 12/08/11) " I first tried the jumper cable test by attaching the black wire to the negative battery post "

That's a very good way to blow up a battery. Didn't you read tip # 43? You do not have to be new to tractors to read & follow instructions. Do NOT ever hook up jumper cables to the battery posts.

" FYI, the voltage across the battery terminals reads 12.8V. I obtain the same reading when touching the common lead of the volt-meter to the tractor frame. This leads me to believe my battery's negative ground connection is good."

No, that doesn't tell you jack spit.

You have a low voltage problem most likely caused by poor connections. Remove all of the cables & clean every single ground. Both posts on the battery, the ends of both cables, the sheetmetal at the battery box, & the stud on the solenoid.

" However, the dust on the copper bar from the solenoid post to the starter post sure did vibrate when I pushed the start button! I assume that means my connections are good and probably indicates the mating surface between the block and starter is good too. "

No. It means you have a poor connection.

Loosen the starter bolts. Jiggle the starter some & it will pull away from the block. Then, put nuts on the bolts to keep the starter from coming apart. (tip # 36)
50 Tips

Bruce (VA), thanks for your advice. I really am trying to read everything, follow directions, and not do something stupid. I failed to mention that I had the positive battery cable disconnected while using the jumper cable, and to be clear, I was not jumping the tractor from a car or other energy source. I was simply using the jumper cables in place of the + battery cable and the battery ground wire to test if I had bad or overly corroded battery wires.

I will clean the mating space between the starter and block next as well as all connections on the starter and solenoid. Then it's anther test. I will let you know what happens. Thanks for your help.

 

[Bruce (VA)]

" I failed to mention that I had the positive battery cable disconnected while using the jumper cable"

Good!

Post back w/ results or more questions.

The last 'clicking solenoid' problem I had was caused by worn threads on the solenoid post. It all "looked good". Regardless, I pulled the cable off, cleaned it up & tried to put it back on. No go. The nut would just spin on the post.

 

[36 Coupe]

Dont Assume it. prove it.Nuts should be 5/16x 18.Sanding the starter to block junction is a a feel good job as there are 2 more steel to aluminum joints.I think the current flows thru the mounting bolts to the front plate and ground brushes.You could put an insulator between the starter and block and still get good cranking.You may have a locked starter.I would check that FIRST..

 

[36 Coupe]

Next time that happens run a 5/16x18 die on the stud.A new brass nut and the solenoid is saved.Still wonder why fine threads are used on brass and copper bolts and studs.

 

[TheOldHokie]

(quoted from post at 08:53:51 12/09/11) Dont Assume it. prove it.Nuts should be 5/16x 18.Sanding the starter to block junction is a a feel good job as there are 2 more steel to aluminum joints.I think the current flows thru the mounting bolts to the front plate and ground brushes.You could put an insulator between the starter and block and still get good cranking.You may have a locked starter.I would check that FIRST..

Current is going to flow through any and every conductive path there is. I second checking for a jammed starter bendis - happens a lot with these exact symptoms.

TOH

 

[whaNcock]

Now the adventure begins! I worked on pulling the starter this morning with my 5/16 nuts (thanks, 36 coupe) in hand per tip #36. But, having never removed an 8N starter before and only knowing what I see in the FO-4 exploded diagrams, I am on my humbling journey through the school of hard knocks.

After loosening the long starter bolts and being careful to ensure they were just slightly disengaged from the block, I slowly worked the starter housing to towards the tractor's front and immediately realized the block drain and dipstick would not allow me to fully pull the starter. I drained the coolant from the radiator pet-cock valve and removed the dipstick. (Pic #3)

Upon working the starter to the left for the second time, I realized something was wrong when I could see the armature. Using a flashlight I could also see the brushes were out of their seats and the first word that came to my mind was "toothpicks" thanks to 50 Tips. I realized the plate next to the block had stuck to the block and my 5/16 nuts were now worthless. (Pic #4)

I got the housing off and now have what's seen in Pic #5. I pulled lightly on the armature, and it didn't budge. I also placed a flat-head screwdriver in the joint between the block and plate and tapped a few times lightly with a hammer around the joint, but nothing budged or seemed to loosen. Before I try pulling the armature out with more force, I want to get some expert advice on anything else I should check or do at this point.

Don't forget that I am a complete novice. Thanks.

 

[whaNcock]

(quoted from post at 07:44:20 12/09/11)

(quoted from post at 08:53:51 12/09/11) Dont Assume it. prove it.Nuts should be 5/16x 18.Sanding the starter to block junction is a a feel good job as there are 2 more steel to aluminum joints.I think the current flows thru the mounting bolts to the front plate and ground brushes.You could put an insulator between the starter and block and still get good cranking.You may have a locked starter.I would check that FIRST..

Current is going to flow through any and every conductive path there is. I second checking for a jammed starter bendis - happens a lot with these exact symptoms.

TOH

Can you provide a way for me to check for a jammed bendis? I've done some additional research in the archives of this forum and seen suggestions like "put the tractor in 3rd gear and rock it back and forth" to help unjam the bendis. Then, supposedly while I'm looking down the shaft of the armature towards the rear of the tractor, I can push the down towards 7-8 o'clock moving the bendix to the 2 o'clock position and wiggle it out. I certainly need all the advice I can get at this point. Thanks.

 

[Bruce (VA)]

Tnx!

Will do.

 

[Bruce (VA)]

" Don't forget that I am a complete novice."

Nothing wrong w/ that; just keep reminding us of it & asking for advice before you do something. But, on the other hand.....doing it wrong is a great teacher!

Spray the starter plate/block mating area w/ PB Blaster & let it set overnight. Get a chisel (not a screwdriver - use the correct tool)and gently tap in the groove. You can't hurt the block w/ the chisel, but that end cap is aluminum. Once you get it loose, push the nose of the armature down & left up the bendix end & pull it forward.

There are plenty of ways to put the starter back together. Some folks use alligator clips, toothpicks or dental floss to hold the brushes back. Others remove the metal band and paper gasket, then put the starter back together. Pull the brushes up thru the holes that the band was covering. Use long nose pliers to pull the brush springs up. Move each one to the right and let them rest on the brush holder. Put each brush into the holder. Pull up each spring and place it on each brush. Put the gasket and metal band back on.

Caution: while the starter is off, resist the temptation to screw with the bendix. If you extend the bendix, and it is not the OEM bendix w/ the big spring, you will have a hard time getting the starter installed.

To install the starter, keep it close to the block while pulling the front of it up and pushing the bendix back into the hole. The bendix has to go behind the flywheel; your job is to get it over the flywheel. Grinding out an egg shape at the 2 o'clock position before you put it back will make your life easier.

Lastly, while the starter is off, polish the block & all starter mating surfaces w/ sandpaper to insure a good electrical ground. First, clean the mating area between the barrel and rear plate. Then, clean the mating surfaces where the aluminum rear plate meets the bell housing. The starter's ground circuit is not only through the two long bolts but from the barrel to the rear plate & then to the bell housing as well.
50 Tips

 

[whaNcock]

(quoted from post at 16:58:05 12/09/11) " Don't forget that I am a complete novice."

Nothing wrong w/ that; just keep reminding us of it & asking for advice before you do something. But, on the other hand.....doing it wrong is a great teacher!

Spray the starter plate/block mating area w/ PB Blaster & let it set overnight. Get a chisel (not a screwdriver - use the correct tool)and gently tap in the groove. You can't hurt the block w/ the chisel, but that end cap is aluminum. Once you get it loose, push the nose of the armature down & left up the bendix end & pull it forward.

There are plenty of ways to put the starter back together. Some folks use alligator clips, toothpicks or dental floss to hold the brushes back. Others remove the metal band and paper gasket, then put the starter back together. Pull the brushes up thru the holes that the band was covering. Use long nose pliers to pull the brush springs up. Move each one to the right and let them rest on the brush holder. Put each brush into the holder. Pull up each spring and place it on each brush. Put the gasket and metal band back on.

Caution: while the starter is off, resist the temptation to screw with the bendix. If you extend the bendix, and it is not the OEM bendix w/ the big spring, you will have a hard time getting the starter installed.

To install the starter, keep it close to the block while pulling the front of it up and pushing the bendix back into the hole. The bendix has to go behind the flywheel; your job is to get it over the flywheel. Grinding out an egg shape at the 2 o'clock position before you put it back will make your life easier.

Lastly, while the starter is off, polish the block & all starter mating surfaces w/ sandpaper to insure a good electrical ground. First, clean the mating area between the barrel and rear plate. Then, clean the mating surfaces where the aluminum rear plate meets the bell housing. The starter's ground circuit is not only through the two long bolts but from the barrel to the rear plate & then to the bell housing as well.
50 Tips

This is great. Thanks for taking the time to provide details. I'll get to work on it again in the morning.

 

[Hobo,NC]

Tip "voltage drop test" Google it and also some good info on youtube... Know'n how to do a voltage drop test should be a requirement to get yer Guru patch but evidently not ...

 

[whaNcock]

(quoted from post at 20:11:53 12/09/11)
Tip "voltage drop test" Google it and also some good info on youtube... Know'n how to do a voltage drop test should be a requirement to get yer Guru patch but evidently not ...

Thanks for this advice Hobo,NC! I went to YouTube as you suggested and watched two videos on Voltage Drop Testing. They were VERY informative. I know how to use a multi-meter, but I've never performed this type of testing. It will become a regular part of my diagnostic troubleshooting moving forward.

I found this video particularly helpful: http://www.youtube.com/watch?v=XhRPLgH6uZg&feature=related

 

[whaNcock]

I'm still unable to remove the starter armature from the tractor. I've sprayed the joint shown in Pic #5 with Kroil three times over 1.5 days and taken several trips to the garage to try and free it using a chisel in the joint. Against previous advice, I finally resorted to using a large, flat-head screwdriver and did see the plate move 1/16" to the left, but when I pulled the screwdriver blade out of the joint, the plate snapped back to its original position.

I've rocked the tractor back and forth in neutral and every gear, including Reverse, thinking that it might help free the Bendix from a bind, if that's what's occurring, but to no avail.

I've also tapped around the armature gently with a rubber mallet in an effort to loosen it.

Any suggestions as to what I should try next?

 

[JMOR]

(quoted from post at 10:27:15 12/12/11) I'm still unable to remove the starter armature from the tractor. I've sprayed the joint shown in Pic #5 with Kroil three times over 1.5 days and taken several trips to the garage to try and free it using a chisel in the joint. Against previous advice, I finally resorted to using a large, flat-head screwdriver and did see the plate move 1/16" to the left, but when I pulled the screwdriver blade out of the joint, the plate snapped back to its original position.

I've rocked the tractor back and forth in neutral and every gear, including Reverse, thinking that it might help free the Bendix from a bind, if that's what's occurring, but to no avail.

I've also tapped around the armature gently with a rubber mallet in an effort to loosen it.

Any suggestions as to what I should try next?

guess you are unable to rock it hard/far enough to see fan blade move?

 

[whaNcock]

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

 

[TheOldHokie]

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

 

[whaNcock]

I can certainly pull my tractor forward while it's in gear. I'll wait another day to see if there are any other suggestions. If not, I'll put it in 4th gear and pull it slowly forward.

What's the likelihood a gear or other part will break doing this?

Thanks again for all of the advice.

 

[R Geiger]

(quoted from post at 02:33:26 12/13/11) I can certainly pull my tractor forward while it's in gear. I'll wait another day to see if there are any other suggestions. If not, I'll put it in 4th gear and pull it slowly forward.

What's the likelihood a gear or other part will break doing this?

Thanks again for all of the advice.

You should be able to turn the engine over by going in the timing hole on the other side of the engine. Should have a tear drop shaped cover on it. Use a large screwdriver to plr againste the flywheel teeth. This will tell you if it will turn over before you try towing in 4 gear. In 4th you should b e able to see the fan move when you rock the machine back and forth.

 

[whaNcock]

(quoted from post at 07:48:25 12/12/11)

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

I'll ask again since I didn't get a response last time. If I slowly pull my tractor forward while it's in 4th gear, is it likely that I will break something? Maybe it should be obvious to me, but I'm a novice...why will pulling the tractor while it's in gear free the bendix?

Is the armature's pinion always meshed with the fly wheel's ring gear? I'm having difficulty understanding "what" is stuck. Thanks.
Thanks!

 

[R Geiger]

(quoted from post at 05:30:56 12/14/11)

(quoted from post at 07:48:25 12/12/11)

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

I'll ask again since I didn't get a response last time. If I slowly pull my tractor forward while it's in 4th gear, is it likely that I will break something? Maybe it should be obvious to me, but I'm a novice...why will pulling the tractor while it's in gear free the bendix?

Is the armature's pinion always meshed with the fly wheel's ring gear? I'm having difficulty understanding "what" is stuck. Thanks.
Thanks!

I suggested you try rotating the engine from the timing port.If the engine turns over that way then you should be good to go with twing it a bit.
The bendix gears are not always engaged with the flywheel gear. Once the engine rpm is higher than the starter rpm they should disengage fom the ring geear. If you cannot get it out you may have to split the tractor and see what is going on in there. The bendix may be broken and jambed somehow.
Good luck

 

[whaNcock]

(quoted from post at 13:46:34 12/13/11)

(quoted from post at 05:30:56 12/14/11)

(quoted from post at 07:48:25 12/12/11)

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

I'll ask again since I didn't get a response last time. If I slowly pull my tractor forward while it's in 4th gear, is it likely that I will break something? Maybe it should be obvious to me, but I'm a novice...why will pulling the tractor while it's in gear free the bendix?

Is the armature's pinion always meshed with the fly wheel's ring gear? I'm having difficulty understanding "what" is stuck. Thanks.
Thanks!

I suggested you try rotating the engine from the timing port.If the engine turns over that way then you should be good to go with twing it a bit.
The bendix gears are not always engaged with the flywheel gear. Once the engine rpm is higher than the starter rpm they should disengage fom the ring geear. If you cannot get it out you may have to split the tractor and see what is going on in there. The bendix may be broken and jambed somehow.
Good luck

I looked for the "timing hole" you mentioned and the teardrop shaped cover, but did not see that. I was looking on the other side of the tractor, directly opposite to the starter. Maybe I need more detailed directions.

 

[TheOldHokie]

(quoted from post at 16:30:56 12/13/11)

(quoted from post at 07:48:25 12/12/11)

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

I'll ask again since I didn't get a response last time. If I slowly pull my tractor forward while it's in 4th gear, is it likely that I will break something? Maybe it should be obvious to me, but I'm a novice...why will pulling the tractor while it's in gear free the bendix?

Is the armature's pinion always meshed with the fly wheel's ring gear? I'm having difficulty understanding "what" is stuck. Thanks.
Thanks!

Sorry - thought I would give someone else a chance I would say no chance of damage if you exercise good common sense. I've had to drag them 20-30 feet with the rear wheels sliding before the gear let go and nothing was ever damaged.

At rest the bendix gear is not engaged with the ring gear. When you energize the starter the centrifugal forces on the bendix (in Physics 101 Dr Loh would have more accurately called it inertia) cause the starter gear to slide rearward on the starter shaft and engage the teeth on the ring gear allowing the starter to "crank" the motor. When the motor catches and starts running on its own it turns faster than the starter gear which causes the starter gear to slide forward on the shaft and disengage from the ring gear.

The starter bendix gear sometimes gets "cocked" in the ring gear on the flywheel. When that happens it wedges and prevents the starter from turning the motor and vice-versa. By putting teh tractor in gear and pulling it forward you are turning the ring gear in the direction of the running motor in the hope that it will coax the bendix gear to straighten and/or disengage. The fact that you cannot free the starter from the block is a strong indication that something is wedged inside.

TOH

 

[whaNcock]

(quoted from post at 14:02:03 12/13/11)

(quoted from post at 16:30:56 12/13/11)

(quoted from post at 07:48:25 12/12/11)

(quoted from post at 10:42:41 12/12/11)

(quoted from post at 07:37:46 12/12/11)

I have been watching the fan blade while rocking but have not seen it move. Does it matter which gear the tractor is in while rocking? I can find someone to help me rock it more forcefully if that's called for.

I have towed my 8N with another tractor to unjam the bendix. Used fourth gear and towed it forward to simulate the motor starting. Rear tire left a long rut in the gravel before the motor finally came free....

TOH

I'll ask again since I didn't get a response last time. If I slowly pull my tractor forward while it's in 4th gear, is it likely that I will break something? Maybe it should be obvious to me, but I'm a novice...why will pulling the tractor while it's in gear free the bendix?

Is the armature's pinion always meshed with the fly wheel's ring gear? I'm having difficulty understanding "what" is stuck. Thanks.
Thanks!

Sorry - thought I would give someone else a chance I would say no chance of damage if you exercise good common sense. I've had to drag them 20-30 feet with the rear wheels sliding before the gear let go and nothing was ever damaged.

At rest the bendix gear is not engaged with the ring gear. When you energize the starter the centrifugal forces on the bendix (in Physics 101 Dr Loh would have more accurately called it inertia) cause the starter gear to slide rearward on the starter shaft and engage the teeth on the ring gear allowing the starter to "crank" the motor. When the motor catches and starts running on its own it turns faster than the starter gear which causes the starter gear to slide forward on the shaft and disengage from the ring gear.

The starter bendix gear sometimes gets "cocked" in the ring gear on the flywheel. When that happens it wedges and prevents the starter from turning the motor and vice-versa. By putting teh tractor in gear and pulling it forward you are turning the ring gear in the direction of the running motor in the hope that it will coax the bendix gear to straighten and/or disengage. The fact that you cannot free the starter from the block is a strong indication that something is wedged inside.

TOH

That makes a lot of sense. I thought some type of centrifugal clutch mechanism might be involved, but I couldn't see it while looking at the exploded view of the starter in my FO-4 manual. (My physics 101 teacher at Va Tech was Prof. Coffee, a rather young and difficult to tolerate Englishman.) Now I get it!

 

[TheOldHokie]

(quoted from post at 17:10:23 12/13/11)
That makes a lot of sense. I thought some type of centrifugal clutch mechanism might be involved, but I couldn't see it while looking at the exploded view of the starter in my FO-4 manual. (My physics 101 teacher at Va Tech was Prof. Coffee, a rather young and difficult to tolerate Englishman.) Now I get it!

In 1969 it was VPI and AP Physics 101 with Dr Hy Loh. If you thought the Englishman was hard to understand you wouldn't have like Dr Loh any better. Very agreeable and helpful man otherwise. And yes - his name was the butt of many jokes and bad puns. Fortunately mathematics has no accent when written on the chalkboard.....

TOH

 

[R Geiger]

Picture shows the timing port cover. Only on 8ns with side dist. early 8ns and 9n and 2ns do not have it.
Remove the screw and and cover and you will see the flywheel teeth.

 

[R Geiger]

I went back to your orginial post and saw that you did say front mount dist. You do not have the timing hole. sorry for the confusion.

 

[whaNcock]

(quoted from post at 14:33:49 12/13/11) I went back to your orginial post and saw that you did say front mount dist. You do not have the timing hole. sorry for the confusion.

Thanks for clarifying!

 

[whaNcock]

I finally got my tractor out of the garage and pulled it in 4th gear twice about 150' each time at 2-4 mph with a truck. In between pulls, the tractor was pulled backwards in neutral to the original starting position. The first 35' of the pull was on concrete with the remainer in the wet yard. I realize that isn't ideal because the tires need to experience friction to put load on the flywheel/bendix, but that's the best I could do. The starter is still stuck as before. I tried gently tapping the gap between the starter plate and frame with a hammer and chisel as before to see if the starter had loosened any, but it has not.

The rear tires skidded mostly and occasionally spun slightly in opposite directions (just a few inches of rotation) while the tractor was pulled.

I'm beginning to question whether the bendix is stuck or if it's possibly something else in the engine causing the lock-up. I don't want to jump to conclusions though. Any suggestions on what my next step should be?

Thanks.

 

[TheOldHokie]

(quoted from post at 16:24:22 12/15/11) I finally got my tractor out of the garage and pulled it in 4th gear twice about 150' each time at 2-4 mph with a truck. In between pulls, the tractor was pulled backwards in neutral to the original starting position. The first 35' of the pull was on concrete with the remainer in the wet yard. I realize that isn't ideal because the tires need to experience friction to put load on the flywheel/bendix, but that's the best I could do. The starter is still stuck as before. I tried gently tapping the gap between the starter plate and frame with a hammer and chisel as before to see if the starter had loosened any, but it has not.

The rear tires skidded mostly and occasionally spun slightly in opposite directions (just a few inches of rotation) while the tractor was pulled.

I'm beginning to question whether the bendix is stuck or if it's possibly something else in the engine causing the lock-up. I don't want to jump to conclusions though. Any suggestions on what my next step should be?

Thanks.

If the starter won't come out something is wrong there at the minimum. Split at the bell housing at least enough to peek inside would probably be my next step.

TOH

 

[JMOR]

(quoted from post at 16:24:22 12/15/11) I finally got my tractor out of the garage and pulled it in 4th gear twice about 150' each time at 2-4 mph with a truck. In between pulls, the tractor was pulled backwards in neutral to the original starting position. The first 35' of the pull was on concrete with the remainer in the wet yard. I realize that isn't ideal because the tires need to experience friction to put load on the flywheel/bendix, but that's the best I could do. The starter is still stuck as before. I tried gently tapping the gap between the starter plate and frame with a hammer and chisel as before to see if the starter had loosened any, but it has not.

The rear tires skidded mostly and occasionally spun slightly in opposite directions (just a few inches of rotation) while the tractor was pulled.

I'm beginning to question whether the bendix is stuck or if it's possibly something else in the engine causing the lock-up. I don't want to jump to conclusions though. Any suggestions on what my next step should be?

Thanks.

ounds REALLY stuck! Think you have been given about all the tips I have seen/heard on that one. Maybe....

 

[whaNcock]

(quoted from post at 13:49:03 12/15/11)

(quoted from post at 16:24:22 12/15/11) I finally got my tractor out of the garage and pulled it in 4th gear twice about 150' each time at 2-4 mph with a truck. In between pulls, the tractor was pulled backwards in neutral to the original starting position. The first 35' of the pull was on concrete with the remainer in the wet yard. I realize that isn't ideal because the tires need to experience friction to put load on the flywheel/bendix, but that's the best I could do. The starter is still stuck as before. I tried gently tapping the gap between the starter plate and frame with a hammer and chisel as before to see if the starter had loosened any, but it has not.

The rear tires skidded mostly and occasionally spun slightly in opposite directions (just a few inches of rotation) while the tractor was pulled.

I'm beginning to question whether the bendix is stuck or if it's possibly something else in the engine causing the lock-up. I don't want to jump to conclusions though. Any suggestions on what my next step should be?

Thanks.

ounds REALLY stuck! Think you have been given about all the tips I have seen/heard on that one. Maybe....

Thanks for the laugh...I needed it!

 

[whaNcock]

(quoted from post at 13:41:21 12/15/11)

(quoted from post at 16:24:22 12/15/11) I finally got my tractor out of the garage and pulled it in 4th gear twice about 150' each time at 2-4 mph with a truck. In between pulls, the tractor was pulled backwards in neutral to the original starting position. The first 35' of the pull was on concrete with the remainer in the wet yard. I realize that isn't ideal because the tires need to experience friction to put load on the flywheel/bendix, but that's the best I could do. The starter is still stuck as before. I tried gently tapping the gap between the starter plate and frame with a hammer and chisel as before to see if the starter had loosened any, but it has not.

The rear tires skidded mostly and occasionally spun slightly in opposite directions (just a few inches of rotation) while the tractor was pulled.

I'm beginning to question whether the bendix is stuck or if it's possibly something else in the engine causing the lock-up. I don't want to jump to conclusions though. Any suggestions on what my next step should be?

Thanks.

If the starter won't come out something is wrong there at the minimum. Split at the bell housing at least enough to peek inside would probably be my next step.

TOH

That seems to be the next thing to try. I found a few videos on YouTube about splitting an 8N and have seen several things in this forum, so it shouldn't be too big of a deal even though I've never done it, much less seen it, before. I'll make sure I have some help there when I do it and will write back with the results.

 

[36 Coupe]

A cylinder full of gasoline or water can give a novice much fun.

 

[whaNcock]

I split my tractor this morning and found what seems to be the cause of the problem. As you can see in Pic #6 below, the drive shaft of the bendix had backed out, and the lip of the bendix threads caught on the pinion. This caused the starter to be locked up. I took a pair of pliers and turned the pinion CCW (you can see some plier marks on the pinion in Pic #7) until the lip came off the pinion and popped back into the proper position. Once this happened, I easily removed the starter.

I found the threads of the starter drive shaft (part 22 of Fig. 183 in the FO-4 manual) all boogered up. I suspect this shaft backed out somehow over time, and this allowed the hang up shown in Pic #6.

I'm wondering if I should buy a new starter drive shaft and use existing parts to rebuild or should I buy a whole drive assembly. I've seen others on this forum say, "don't disassemble the bendix," but I've already done that. What do the gurus think?

Also, anything else I should do while my tractor is in its current state? (I did find a missing thermostat, and I'm going to fix/replace my rusty gas tank.) Thanks for your help!

 

[R Geiger]

I would buy a new style Bendix from this site and put everything back together. New brushes also if they look worn. Good luck

 

[TheOldHokie]

(quoted from post at 15:49:14 12/19/11) I would buy a new style Bendix from this site and put everything back together. New brushes also if they look worn. Good luck

+1 on that suggestion. In your picture it looks like the cross pin that retains the bendix on the starter motor shaft worked it's way out - possibly the cause of the problem. Also looks like a pretty new bendix.....

TOH