860 fires but won't start

[Delgriffith]

I'm stumped. I was running my 860 for snow removal and it was running fine then in the middle of a pass it just quit. No sputtering or anything, almost like I shut the key off. I thought maybe the carb float stuck as that has happened before but only when it sits. Tapped the carb bowl with a piece of metal and tried to restart. It fired a little but wouldn't start. In the process of troubleshooting I left the key on accidentally for several minutes and burned up my electronic ignition sensor. I bought a new model from Pertronix that was updated to have burn up protection (Ignitor II). Installed it and now I'm trying to start the tractor with no luck. It fires and is so close to starting but just won't. I have it plugged in and the engine is warm to the touch. So far I have tried:

Adjust timing each way in case the new sensor was a little different, it seems to fire best at the original setting roughly.

Check spark with inline test light, all 4 cylinders are indicating spark. Also checked by watching the plugs when pulled out.

Pulled the carb and went through it hitting the passages with compressed air and carb cleaner

Check compression, 115-125 all 4 cylinders

Check fuel flow, pours out of the sediment bowl fine.

Check fuel level (duh) over 1/2 tank

It is a 12v conversion if that helps.

Very frustrating!!!!

 

[Steve in IL]

Have you tried spraying fuel into the carb intake? Just remove the tube to the air cleaner, and use an old spray bottle to spray in some fuel. What happens?

 

[Steve in IL]

My go-to test for this condition is to remove the pipe/hose that goes from the air cleaner to the carburetor, the spray (use an old spray bottle) some gasoline directly into the carburetor. Immediately, try to start. Does it fire? If it does, you have a fuel supply issue. If it does not fire, you likely have an ignition issue. One other trick... I like to start cranking with no choke. If the engine does not fire, slowly start pulling the choke until closed. In that manner, you minimize the chance of an over rich/flooded condition. Also, if you do get it to fire with spray bottle gas, you can keep it running by continuing to spray some gas into the carb. I can't tell you the number of engines I've "fixed" by getting it to run in this manner, and a bit of heat/vibration/vacuum clears whatever was in the carb, and all runs well.

Give the above a try, and keep up posted with what you find. Good luck!

 

[Delgriffith]

My go-to test for this condition is to remove the pipe/hose that goes from the air cleaner to the carburetor, the spray (use an old spray bottle) some gasoline directly into the carburetor. Immediately, try to start. Does it fire? If it does, you have a fuel supply issue. If it does not fire, you likely have an ignition issue. One other trick... I like to start cranking with no choke. If the engine does not fire, slowly start pulling the choke until closed. In that manner, you minimize the chance of an over rich/flooded condition. Also, if you do get it to fire with spray bottle gas, you can keep it running by continuing to spray some gas into the carb. I can't tell you the number of engines I've "fixed" by getting it to run in this manner, and a bit of heat/vibration/vacuum clears whatever was in the carb, and all runs well.

Give the above a try, and keep up posted with what you find. Good luck!

Thanks for the suggestion. I didn't exactly do that but I did spray starting fluid in the carb and it seems to have no effect. It just fires enough to kick the starter off the flywheel and doesn't run for any length of time. Come to think about it, this suggests it's spark related and when I think about it it kind of seems like it's only trying to run on like 1-2 cylinders. My distributor cap is new though and the plugs seem to fire fine when pulled. Wonder if this is somehow related to my electronic ignition.

 

[Jim L WA]

I don't know about the 860, or your E.I., but some ignition systems have a start circuit that bypasses a resister during cranking and then cuts out so the tractor can run on the run circuit. Others will chime in on this.

 

[ErnieD]

Thanks for the suggestion. I didn't exactly do that but I did spray starting fluid in the carb and it seems to have no effect. It just fires enough to kick the starter off the flywheel and doesn't run for any length of time. Come to think about it, this suggests it's spark related and when I think about it it kind of seems like it's only trying to run on like 1-2 cylinders. My distributor cap is new though and the plugs seem to fire fine when pulled. Wonder if this is somehow related to my electronic ignition.

double check firing order on your cap
pull spark plugs off ~3/8". this increases spark voltage and will fire off wet fouled plugs

 

[Delgriffith]

So my last idea was to switch it back to the points system. I did that and it fired right up. So far I'm not very impressed with the electronic ignition. I don't know what's up with it but obviously something isn't right. At least I can get the driveway clear now.

 

[Ozlander]

So my last idea was to switch it back to the points system. I did that and it fired right up. So far I'm not very impressed with the electronic ignition. I don't know what's up with it but obviously something isn't right. At least I can get the driveway clear now.

It may not have been wired properly.

 

[Sean in PA]

It may not have been wired properly.

He said that it was running fine and then just quit. Sounds like he had it wired correctly.

 

[bob p mn]

I would talk to Pertronix's Tech support guys I have done that a couple of times and they will give you alot of information on installing correctly and troubleshooting. I found out after trying to cleanup some other guys installs that clean grounds and good connections are of utmost importance to the longevity of the electronics.

 

[soaked]

Agree call Pertronix.
If you are using a 3.0 ohm coil with the new 91244A ignitor ll, my theory is that 3.0 ohms is way too much resistance, and is causing weak intermittent spark.
Was told Ignitor ll is designed to pair with flame thrower ll coils, that have 0.6 ohms. Call and see if you get the same recommendation.
Did the tractor have suppression plug wires when the 1244A ignitor 1 was installed last summer? If no, RFI may have fried the module.( not key being left on a few minutes.)

 

[Ozlander]

He said that it was running fine and then just quit. Sounds like he had it wired correctly.

No.
He said he changed the electronic ignition, and it wouldn't start until he put the points back in.

 

[Delgriffith]

No.
He said he changed the electronic ignition, and it wouldn't start until he put the points back in.

The electronic ignition is two wires, and I ran the pertronix test proceedure to determine it had gone bad after it had been running fine for several months. I was not aware that leaving the key on could damage it so that is probably why it failed. I ordered a new model that has a protection circuit in it to prevent burning up if the key is left on, but it is also just two identical wires as my old one. I installed it the same way and it was apparently only firing some of the time. When I put an inline spark indicator on, all cylinders indicated they were firing, just not at the right time or often enough.

 

[Delgriffith]

Agree call Pertronix.
If you are using a 3.0 ohm coil with the new 91244A ignitor ll, my theory is that 3.0 ohms is way too much resistance, and is causing weak intermittent spark.
Was told Ignitor ll is designed to pair with flame thrower ll coils, that have 0.6 ohms. Call and see if you get the same recommendation.
Did the tractor have suppression plug wires when the 1244A ignitor 1 was installed last summer? If no, RFI may have fried the module.( not key being left on a few minutes.)

I have the same coil that came with my 12v conversion. I don't believe there is any RF suppression in my plug wires. I had not read about that potentially damaging the sensors. This coil issue could be the problem as I looked up the coil I have which I think is a UC15T and it is sometimes being sold as "for use 12v vehicles without electronic ignition". I may give pertronix a call just to confirm the intermittent behavior I was having with their experience. Thanks for the suggestion.

 

[soaked]

Weren't there folded paper instuctions that came in the box?

They require your new ignitor ll must be used with suppression ignition wires.

Since it never started, its likely ok.

Running with non suppression wires can fry a module in as little as 2 hrs or it may take 6 months. (thats my understanding)

You're gonna need a 0.6 ohm flame thrower ll coil, and suppression wires if following Pertronix instrctions/ recommendations for Ignitor ll.

Best to call Pertronix.

 

[tractorford]

The electronic ignition is two wires, and I ran the pertronix test proceedure to determine it had gone bad after it had been running fine for several months. I was not aware that "leaving the key on could damage it so that is probably why it failed." I ordered a new model that has a protection circuit in it to prevent burning up if the key is left on, but it is also just two identical wires as my old one. I installed it the same way and it was apparently only firing some of the time. When I put an inline spark indicator on, all cylinders indicated they were firing, just not at the right time or often enough.

ya i made sure to read that part in the instructions and burned it into my brain cortex-- its spooky sometimes forgetting it- when yer fiddling with things, and the tractor is off but the key is set to 'on' but so far with 'this in mind' Ive had good success with my Ignitor 2 with flame thrower2 coil--but i also got the ignitor2 compatible spark plug wires as well..... every now and then tho-- Im like whoa-- whoa-- lets make sure-- I didnt flick that thing 'on while Im jiggling and wiggling with something while the tractor is off--

the ignitor 3 doesnt suffer from this design function-- but it was a bit more than i could budget at the time-- but maybe in the future---