8N with spark issues

[matt1325]

Hey everyone I need a few suggestions as what to troubleshoot next with a tractor I just bought. Ford 8n 6 volt side mount distributor.

It started fine when I bought it a few days ago but since its been in my barn my luck as run out. It will crank and sometimes fire up but it runs really rough and I don't think it is firing on all cylinders. The issue I think is definitely a spark issue I have completed the following:

-Checked battery running a little over 6 volts using multimeter
-Fuel is running out of the bottom of the carb at around a pint every 2-3 minutes so I don't think it is fuel
-New plugs put in. checked plugs initially and they were firing very weak
-Took out the distributor and checked points and they were opening, the distributor looks almost brand new the seller said it was less than a year old.

When I messed with the distributor I put it back in and disconnected the positive battery terminal at the same time and it was stuck with minimal corrosion so I cleaned it and checked the plugs. This time a very strong spark so I was confident it would fire up.

It fired up perfectly and ran on all cylinders smooth for about 1-2 minutes and then went back to rough idle with small puffs of black smoke coming out of the exhaust. I let it run like crap for another 3 minutes and then checked the plugs again afterwards. Back to weak spark.

Compression is above 90 in all cylinders dry and there is no oil in radiator or coolant in oil.

Overall I think I got a good deal and this tractor is in good shape I just can't figure out why the spark is going from weak to strong to weak like this. I am thinking distributor or battery cable as those two variables were the only thing I changed to get a strong spark (even if for only 2 minutes)

Thanks for any help you can give.

 

[duey]

You can jumper across the ignition switch... quick and easy... Or jumper direct- battery to coil.. switches can be erratic.....

 

[Bruce (VA)]

Confirm that you have voltage to the coil. Battery voltage, points open. About half that if the points are closed.




Do you have battery voltage across the points when they are open? (with the points open, put one probe on one side of the points & the other probe on the opposite side of the points) Verify the gap on the points at .025. Then, dress the points by running a piece of card stock or brown paper bag through them. New points sometimes have an anti-corrosive dielectric coating on them & old points can corrode or pick up grease from a dirty feeler gauge or excessive cam lubricant. (I always spray my feeler gauge blade off w/ contact cleaner.) Make sure you have voltage across the points, as in past the insulator on the side of the distributor. That is a very common failure point on sidemounts, along w/ the attached copper strip. It's hard to find a short there because it is usually an intermittent . So 'wiggle' the insulator & the copper strip a bit when you are doing your checking. If you find the short there, the Master Parts catalog lists everything you need on page 154. You can make the strip and you could also make the insulators as well. But, somethings are just easier & in the long run cheaper to buy. Get the strip, 12209, screw 350032-S, 12233 bushing & 12234 insulator & just replace it all.
75 Tips

 

[Tony292]

(quoted from post at 20:19:31 06/05/19) Hey everyone I need a few suggestions as what to troubleshoot next with a tractor I just bought. Ford 8n 6 volt side mount distributor.

It started fine when I bought it a few days ago but since its been in my barn my luck as run out. It will crank and sometimes fire up but it runs really rough and I don't think it is firing on all cylinders. The issue I think is definitely a spark issue I have completed the following:

-Checked battery running a little over 6 volts using multimeter
-Fuel is running out of the bottom of the carb at around a pint every 2-3 minutes so I don't think it is fuel
-New plugs put in. checked plugs initially and they were firing very weak
-Took out the distributor and checked points and they were opening, the distributor looks almost brand new the seller said it was less than a year old.

When I messed with the distributor I put it back in and disconnected the positive battery terminal at the same time and it was stuck with minimal corrosion so I cleaned it and checked the plugs. This time a very strong spark so I was confident it would fire up.

It fired up perfectly and ran on all cylinders smooth for about 1-2 minutes and then went back to rough idle with small puffs of black smoke coming out of the exhaust. I let it run like crap for another 3 minutes and then checked the plugs again afterwards. Back to weak spark.

Compression is above 90 in all cylinders dry and there is no oil in radiator or coolant in oil.

Overall I think I got a good deal and this tractor is in good shape I just can't figure out why the spark is going from weak to strong to weak like this. I am thinking distributor or battery cable as those two variables were the only thing I changed to get a strong spark (even if for only 2 minutes)

Thanks for any help you can give.

Here is a good example of a method to check the distributor/coil/points.

https://m.youtube.com/watch?v=p-vrSWFJzqQ

 

[ScottNC]

What kind of shape is the ignition primary side resister in? When the factory original on my 2N (literally) fell apart, a ceramic one was installed. Started and ran just fine cold - for a short period of time. Once warm it ran poorly and was hard to start. On a whim one day, I grabbed a jumper wire and while the engine tried to idle (sputtering and carrying on), jumpered around the resister; Ran like a top.

Full disclosure: Converted the tractor to 12 volts many years ago. After two 12 volt and the old 6Volt Ford coil failed, a round can coil was installed. As it turned out, once the can coil and the resister were fully warmed up... resistance was too high resulting in weak spark.

 

[Bruce (VA)]

He said it was a 6v side distributor, so it should not have any resistor.
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[Bruce (VA)]

You said " Ford 8n 6 volt side mount distributor."

And you also said " -Took out the distributor and checked points "

So, why are you removing the distributor to check the points?

Do you really have a side distributor?
75 Tips

 

[matt1325]

Thanks for the quick responses. So I am familiar with automobile engine work but my experience with distributors is just changing the cap and rotor button not any internals. It is a 6volt side mount distributor.

I took off the distributor just to see how it worked and visually inspect it. Spun the shaft with my hand to watch the points open and close and just look at it.

I will check the voltage in other places besides the battery this afternoon and watch that youtube video.

I will leave the distributor on this time and test it that way as suggested and post back my findings. Thanks again.

 

[Jim L WA]

Matt, you said, "It fired up perfectly and ran on all cylinders smooth for about 1-2 minutes and then went back to rough idle with small puffs of black smoke coming out of the exhaust. I let it run like crap for another 3 minutes and then checked the plugs again afterwards. Back to weak spark." Have you tried tapping on the carburetor with the handle of a screwdriver or something like that? I'm wondering if the float or needle and seat arn't working. How are you checking for spark? Will the spark NOT jump a 1/4inch gap?

 

[matt1325]

(quoted from post at 09:13:07 06/06/19) Matt, you said, "It fired up perfectly and ran on all cylinders smooth for about 1-2 minutes and then went back to rough idle with small puffs of black smoke coming out of the exhaust. I let it run like crap for another 3 minutes and then checked the plugs again afterwards. Back to weak spark." Have you tried tapping on the carburetor with the handle of a screwdriver or something like that? I'm wondering if the float or needle and seat arn't working. How are you checking for spark? Will the spark NOT jump a 1/4inch gap?

I did use the butt of a hammer to hit the carb a few days ago when I thought it was a fuel issue. I am 100% sure it is spark related at this point. Spark wouldn t jump 1/4 inch gap then took off the rotor and put it back on and adjusted the positive battery cable and it then did bridge 1/4" gap. It ran for 2 minutes perfectly and then idled rough. Cut it off and checked plugs and hey once again would not jump gap.

So overall weak spark, then strong, then back to weak.

 

[Jim L WA]

O.K., it was the puffs of black smoke that got me thinking maybe the idle mixture had gone rich. You might check all the wiring connections under the instrument panel. It could be that when you pulled and cleaned the positive battery post and clamp, you may have bumped something up in there and it cleared up for a couple of minutes. I'm also thinking that this problem has been around for awhile. That may be why the P.O. put a new distributor in it. Did you try bypassing the ignition switch like one of the others suggested?

 

[matt1325]

(quoted from post at 20:19:31 06/05/19) Hey everyone I need a few suggestions as what to troubleshoot next with a tractor I just bought. Ford 8n 6 volt side mount distributor.

It started fine when I bought it a few days ago but since its been in my barn my luck as run out. It will crank and sometimes fire up but it runs really rough and I don't think it is firing on all cylinders. The issue I think is definitely a spark issue I have completed the following:

-Checked battery running a little over 6 volts using multimeter
-Fuel is running out of the bottom of the carb at around a pint every 2-3 minutes so I don't think it is fuel
-New plugs put in. checked plugs initially and they were firing very weak
-Took out the distributor and checked points and they were opening, the distributor looks almost brand new the seller said it was less than a year old.

When I messed with the distributor I put it back in and disconnected the positive battery terminal at the same time and it was stuck with minimal corrosion so I cleaned it and checked the plugs. This time a very strong spark so I was confident it would fire up.

It fired up perfectly and ran on all cylinders smooth for about 1-2 minutes and then went back to rough idle with small puffs of black smoke coming out of the exhaust. I let it run like crap for another 3 minutes and then checked the plugs again afterwards. Back to weak spark.

Compression is above 90 in all cylinders dry and there is no oil in radiator or coolant in oil.

Overall I think I got a good deal and this tractor is in good shape I just can't figure out why the spark is going from weak to strong to weak like this. I am thinking distributor or battery cable as those two variables were the only thing I changed to get a strong spark (even if for only 2 minutes)

Thanks for any help you can give.

So got home later than I thought tonight. I bypassed the ignition switch and nothing, still weak spark at the plugs. Tomorrow I am going to take out the ignition coil and test it for resistance. I also took off the positive battery terminal and scrubbed it really good and didn t see anymore corrosion. I am thinking ignition coil, distributor or generator. I don t know all the contact points for the multimeter but I want to narrow it down instead of replacing everything. The distributor is brand new so I may change the points and condenser as a last resort. buddy told me 6 volts are a pain in the butt and everything has to be perfect. Not a good sign for an ignition newbie.

 

[Bruce (VA)]

The generator has NOTHING to do with your problem.


And it's highly unlikely that your round coil does either.


I'd eliminate points gap & resistance and an insulator short before I moved on to anything else.
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[Indiana Ken]

So, your buddy told you 6 volts are a pain in the butt:

If you follow this forum for a period of time you will find 12 volts does not solve anything basic trouble shooting would not take care of. Converting to 12 volts comes with it's own set of pitfalls to trip you up.

From 1947 to 1952, there were some half million of these tractor built - all with 6 volts - many still running. Follow the advice on this forum and the guys will get you going again and on 6 volts.

BTW - as has been posted check the ignition switch. I changed mine several years back after having similar problems.

Good Luck

 

[matt1325]

(quoted from post at 05:27:07 06/07/19)
So, your buddy told you 6 volts are a pain in the butt:

If you follow this forum for a period of time you will find 12 volts does not solve anything basic trouble shooting would not take care of. Converting to 12 volts comes with it's own set of pitfalls to trip you up.

From 1947 to 1952, there were some half million of these tractor built - all with 6 volts - many still running. Follow the advice on this forum and the guys will get you going again and on 6 volts.

BTW - as has been posted check the ignition switch. I changed mine several years back after having similar problems.

Good Luck

So I am thinking I maybe didn't bypass the starter switch properly last night or maybe I put an alligator clip in the wrong place/position. So I will try that again and also check the distributor again, points and insulator as suggested. My wife is back in town so I will have a second person to crank the engine while I can diagnose. It's a little hard trying to do both by yourself with certain tasks. Will update thanks again for all the responses

 

[matt1325]

Ok so worked some more on it today. It is not the starter switch I am getting over 6volts on both sides and I bypassed it correctly this time and still weak spark. I attempted to check voltage at the ignition coil but the digital multimeter didn t like it. Might have to get an analog one.

I did use the multimeter and checked both sides of the points while cranking and only the right side was getting voltage. I took a couple pictures of the points all the way open. Does this gap look sufficient? I know it may be hard to tell. I am going to clean the points with brown Paper bag

Any other suggestions I feel like it is getting more narrow and pointing to the distributor

 

[shelbym71]

get some point buddy I had same issue on my 39 sings like a champ now with power to spare

 

[matt1325]

(quoted from post at 15:55:02 06/07/19)
Ok so worked some more on it today. It is not the starter switch I am getting over 6volts on both sides and I bypassed it correctly this time and still weak spark. I attempted to check voltage at the ignition coil but the digital multimeter didn t like it. Might have to get an analog one.

I did use the multimeter and checked both sides of the points while cranking and only the right side was getting voltage. I took a couple pictures of the points all the way open. Does this gap look sufficient? I know it may be hard to tell. I am going to clean the points with brown Paper bag

Any other suggestions I feel like it is getting more narrow and pointing to the distributor

Ok worked on it more today. Checked the points and gapped them to spec. No pitting everything looks good. Checked voltage at coil with points open and closed. Checked voltage across points when they were open and they were good. Put everything back together and took off the wire from the distributor to the coil and it would bridge a gap with a nice blue spark so a strong spark is getting that far in the system.

My question is how often should this wire provide spark to the rotor and plugs because everything seems random. It will fire 4 quick times then pause and fire twice then pause and fire maybe once. Shouldn t there be a consistent times fire for the plugs so that the engine runs well? How many sparks per minute should I be getting at the plugs?

I also now am going back to possibly a fuel issue since the spark is strong but just seems intermittent. I took off the carb and cleaned it. It started but just rough idled like it has been for a week now. It sounds like sometimes it wants to hit full rpms but does so for a second and then idles like crap and dies a minute or two then just will not start back up. Maybe could be fuel related???

 

[ScottNC]

(quoted from post at 05:34:13 06/06/19) He said it was a 6v side distributor, so it should not have any resistor.
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Huh. Now I'm curious, what is the thing the primary ignition wire runs through on its way to the coil that is attached with flat head, countersunk machine screws to the engine side of the dash, just to the left of the battery? Mine is gone now but as I recall it was of ceramic construction with a horseshoe shaped, spiral wound coil looking thing. Maybe match book size. When I switched to 12 volt I left it in. No ignition problems until it fell apart - outside of a couple Chinese made 12V coils puking.

 

[matt1325]

Ok so the timing was off so that s fixed now and I am getting strong spark to the secondary ignition coil but still not to the plugs. Any suggestions besides new cap rotor and wires? Plugs are brand new and those are the only parts between that could cause a loss of spark right?

After that I m stumped anymore suggestions?

 

[Tony292]

(quoted from post at 13:15:28 06/09/19) Ok so the timing was off so that s fixed now and I am getting strong spark to the secondary ignition coil but still not to the plugs. Any suggestions besides new cap rotor and wires? Plugs are brand new and those are the only parts between that could cause a loss of spark right?

After that I m stumped anymore suggestions?

I had intermittent spark and issues starting a few weeks ago. Fixed it by replacing the coil (readings were good but had corrosion on the tab) and also had a bad ballast resistor (rusted bad and couldn t get a good reading). I complicated my case a bit because I wanted to install a pertronix ignitior to replace the points while I was in there. The YouTube video I posted a link to earlier in this thread helped me see what a good system should do and you can take the distributor off the tractor and check it very easily. Since yours is a side mount might be a little different but the theory is all the same.

Have you checked your ballast resistor and coil? These parts are cheap and easily replaced. And the best part is if you determine your old one was good you can keep it for a spare!!! I love having spare parts around. Makes troubleshooting the next time mich easier.

 

[R Geiger]

Side mount dist machines do not have a ballast resistor.