Coil problem?

[RealJeep]

I got the old 77 Kohler running on the 1450 but after it warms up it starts backfiring and then shuts off. The carb seems fine and I'm thinking the coil is the culprit as it was pretty hot. Suggestions/thoughts?

 

[digger]

I got the old 77 Kohler running on the 1450 but after it warms up it starts backfiring and then shuts off. The carb seems fine and I'm thinking the coil is the culprit as it was pretty hot. Suggestions/thoughts?

Change out the condenser with a known good one.

 

[Eric Wittersheim]

I have a similar issue with my 1250. I have changed my condenser and that didn't fix the issue. I'm still working on the problem but with me after 10 minutes of working it (running the mower deck) it would start to lose power big time and die if I don't throttle it down. After changing the coil and condenser I checked my head gasket and sure enough there was a leak. I replaced the gasket but there still was the problem. I then adjusted the valves, and I think it's better (I say that because my deck belt broke, so I tired pulling around a yard roller for a test). I just ordered a new governor spring because mine was bent and maybe that's part of the problem. Hopefully you find out what your issue is.

 

[RealJeep]

I ordered an ignition kit (points, plug, condenser, coil and plug wire) from Amazon for $68. I'm thinking the coil's bad because it got really hot! As soon as the engine cooled off it started and ran fine until it warmed up again. Stay tuned.

 

[dsarow]

A really hot coil is never a good thing,your remarks about resting the tractor for a spell tells me you are on to something. I have a digital temp gun that I have in my arsenal.I use it often,especially on mower bearings,try one,what the heck!Good luck

 

[Eric Wittersheim]

A really hot coil is never a good thing,your remarks about resting the tractor for a spell tells me you are on to something. I have a digital temp gun that I have in my arsenal.I use it often,especially on mower bearings,try one,what the heck!Good luck

What would you say is too hot for a coil? I have one of those guns and will try that.

 

[dsarow]

What would you say is too hot for a coil? I have one of those guns and will try that.

What I do,works for me,is I try to check temps periodically on components for a running average.My 125 is running good,if it starts to stutter, I have a baseline. I do the same with my mower deck bearings.Its a another tool in a guys arsenal.Different tool,but I use a multimeter on my electrical system,trying to react to possible problems before they get serious,it works for me.

 

[ltracey1234]

What do you monitor with your multimeter? TIA

 

[Eric Wittersheim]

What I do,works for me,is I try to check temps periodically on components for a running average.My 125 is running good,if it starts to stutter, I have a baseline. I do the same with my mower deck bearings.Its a another tool in a guys arsenal.Different tool,but I use a multimeter on my electrical system,trying to react to possible problems before they get serious,it works for me.

I like that method. I'll try that on my 1250.

 

[dsarow]

What do you monitor with your multimeter? TIA

I have an older interstate brand battery that shows signs its getting to the end.Since I have two tractors,I alternate,if I plan on using my 125 in a day or so I check the voltage,if its down I slow charge it,after starting and using it,I check voltage while running at full throttle vs volt guage in the dash.My other tractot is a brand new Kubota T2290,its now 2 years old with 50 hours,I wrote the voltages,same way ,while new on battery with marker,as this tractor ages,I have a reference, mainly piece of mind,maybe over kill.Hope I answered your questions

 

[dkirk]

A proper ignition coil for these single-cylinder engine applications should have a minimum primary resistance of 3.2 ohms, measured across the primary terminals (threaded posts). Due to the fact that the dwell time (points closed) is high on a single cylinder-engine, this causes the coils to run hot. There are coils available with a resistance of 1.2 ohms...these are designed to be used either with a ballast resistor or an electronic ignition system. These coils should NOT be used on single-cylinder engines as breaker points will quickly deteriorate due to the high current draw. The original Delco coils had a primary resistance closer to 4.0 ohms which is desirable. Thus, a 12V coil with resistance of 3.2 - 4.0 ohms is ideal for the single-cylinder Kohler.

 

[RealJeep]

I have a similar issue with my 1250. I have changed my condenser and that didn't fix the issue. I'm still working on the problem but with me after 10 minutes of working it (running the mower deck) it would start to lose power big time and die if I don't throttle it down. After changing the coil and condenser I checked my head gasket and sure enough there was a leak. I replaced the gasket but there still was the problem. I then adjusted the valves, and I think it's better (I say that because my deck belt broke, so I tired pulling around a yard roller for a test). I just ordered a new governor spring because mine was bent and maybe that's part of the problem. Hopefully you find out what your is

This is frustrating,
I replaced the coil, condenser and plug wire and it ran great until it warmed up then the same problem. Started sputtering and running rough. It won't even start after it warms up.
Could be the head gasket, I have no idea now.

When I start it from cold, it idles fine. So I let it idle for a while but the warmer it gets the rougher it runs until it just shuts off after a couple backfires.

Any suggestions?

 

[mgonitzke]

Does it have spark when it dies? If so, not an ignition problem. Does pulling the choke help when it tries to die? If so, then there is a fuel issue.

Check the valve lash. If it is set too tight, the valves won't be able to close all the way after the engine warms up.

 

[tkhoffman]

Fuel tank venting properly?
As soon as it dies, unscrew fuel cap and listen for air sucking.
Maybe it time running at high RPM more than engine heat.
Just tossing out an idea

 

[RealJeep]

Update:
Changed all the ignition parts and the points were pretty worn out. Also changed the head gasket while I was at it. A little carb tweaking and I think it'll be just fine.

 

[Eric Wittersheim]

Update:
Changed all the ignition parts and the points were pretty worn out. Also changed the head gasket while I was at it. A little carb tweaking and I think it'll be just fine.

Did that fix your issue? I haven't tried the points yet, I think my carb is fine.

 

[tkhoffman]

Update:
Changed all the ignition parts and the points were pretty worn out. Also changed the head gasket while I was at it. A little carb tweaking and I think it'll be just fine.

What do you consider a 'Real Jeep'?

 

[RealJeep]

Well...
Changed the plug, points, condenser, coil, spark plug wire and got a new carb from iSaveTractors.
Adjusted the governor and put in a new head gasket. It runs pretty good but I'm thinking the K321 is a shaker from the factory no matter what you do to it.
At least it's running now.