Kohler Ch20S

[dropzone]

Hello as you probably already know I am new here. I have a problem with a Kohler Engine the Model number CH20S, Spec 64510. I picked up this engine for a project I have going, anyway the guy told me it was fouling the plug on cylinder 1 he had it in a shop and they said it was fixed but apparently it isn't. I suspect a blown / leaking head gasket or bad valve seal / guide is the cause for the fouled plug. I pulled the plugs and the number one is black while number 2 looks good I tried running it after cleaning and then replacing the plugs in it. It starts fine but will only run for 2 -3 seconds and dies. I checked all the obvious causes like fuel solenoid, air filter, fuel pump and it's getting fire also I don't have the oil sentry hooked up so it's not that. I read where a bad ignition switch will cause it to stop running like this. I am stumped do you guys have any suggestions on the fouled plug and the running problem.

[bgsengine]

First, try 2 new plugs
Second, do a power balance test - Thats when you tale a probe (ice pick) with a jumper wire con9nected between the shank and a good ground, probe the boot on each cylinder one at a time to kill that cylinder - if both sides cause the same drop in RPM, then both cylinders are firing, if not, then the side that results in little to no RPM drop is the side that is not firing

Once you identify the dead cylinder, you can check for spark on that cylinder, and also check valve clearances and a compression test, better yet a leak down test, to identify the cause as to why it is not firing.

Chances are pretty decent that 2 new plugs may fix the problem, but if not, the next likely cause would be a blown head gasket, loose valve seats, and finally, *COULD* be a bad coil on one side.

[StarTech]

Also check for loose or bare wires or connections that could intermittently ground ignition kill circuit. May just disconnect both coils kill wire to isolate the problem. Could be a problem with one coil that is affecting both coils. Also would help determine if the switch is giving problems. This engine uses the fixed CDI timing system. Just some thoughts.

[bobodu]

You mentioned cleaning and replacing the plugs.....did you use NEW plugs?

[dropzone]

You mentioned cleaning and replacing the plugs.....did you use NEW plugs?

Yes I replaced with new plugs. I put a new switch on today with the same results it starts and runs for about 2-3 seconds and dies. I even changed out the fuel lines and the vacuum line but still the same. I checked the fuel pump again by pulling the line going into the carb and I think maybe the fuel pump isn't putting out enough, When I turned it over and the engine fired for a few seconds I only had a trickle of fuel coming out. I will pull the fan shroud and check for shorts in the wires. I really don't think this has anything to do with it but I'm going to ask. I don't have the oil sentry connected that wouldn't have any thing to do with it would it? Another quick question the crank shaft on this engine is 1 1/8" I would like to have a 1" shaft for a Comet clutch I already have. Did they put this motor out with the 1" shaft? If they did does any of you have a P/N? This is an update I found the problem it turned out to be the solenoid, I thought it was working because I unplugged the connector and the engine wouldn't start and when I plugged it back in it would start and die after a few seconds. I took it out and removed the plunger then put it back on now the motor runs like a charm. Now to find a new solenoid I might install a fuel shut off after the pump instead according to the price of a new one. Thanks for your help. I am going to stick around for a while. I have been working on engines of all sizes for more then 30 years and maybe I can be some help from time to time.

[KE4AVB]

When the oil sentry is connected to the oil pressure it only provides either light, alarm, or shut the engine down when there is low oil pressure depending on the manufacture your equipment desire. If it is disconnected; it is disabled so it has no effect on anything.

As for the crankshaft I think that is the smallest PTO diameter for that engine. You may check with a local machine and see what it would to turn down that PTO end or just see if you can get a clutch that will fit it.

[dropzone]

When the oil sentry is connected to the oil pressure it only provides either light, alarm, or shut the engine down when there is low oil pressure depending on the manufacture your equipment desire. If it is disconnected; it is disabled so it has no effect on anything.

As for the crankshaft I think that is the smallest PTO diameter for that engine. You may check with a local machine and see what it would to turn down that PTO end or just see if you can get a clutch that will fit it.

Yea I thought it was the smallest they used. My plan is to get a clutch that will work because I really don't want to tare it down if I don't have to.

[Deere2me]

You mentioned cleaning and replacing the plugs.....did you use NEW plugs?

Yes I replaced with new plugs. I put a new switch on today with the same results it starts and runs for about 2-3 seconds and dies. I even changed out the fuel lines and the vacuum line but still the same. I checked the fuel pump again by pulling the line going into the carb and I think maybe the fuel pump isn't putting out enough, When I turned it over and the engine fired for a few seconds I only had a trickle of fuel coming out. I will pull the fan shroud and check for shorts in the wires. I really don't think this has anything to do with it but I'm going to ask. I don't have the oil sentry connected that wouldn't have any thing to do with it would it? Another quick question the crank shaft on this engine is 1 1/8" I would like to have a 1" shaft for a Comet clutch I already have. Did they put this motor out with the 1" shaft? If they did does any of you have a P/N? This is an update I found the problem it turned out to be the solenoid, I thought it was working because I unplugged the connector and the engine wouldn't start and when I plugged it back in it would start and die after a few seconds. I took it out and removed the plunger then put it back on now the motor runs like a charm. Now to find a new solenoid I might install a fuel shut off after the pump instead according to the price of a new one. Thanks for your help. I am going to stick around for a while. I have been working on engines of all sizes for more then 30 years and maybe I can be some help from time to time.

It will run all day without the solenoid, no problems. The sol. just stops fuel flow to the main jet/ nozzle on shut-down, it has nothing to do with fuel entering the bowl!, so your idea of a valve is pretty much not necessary. Just let the unit idle down a bit before shut-down, is all. A lot of mfg. call the solenoid an "anti-afterfire solenoid".
You need to download a service manual here: http://www.kohlerengines.com/manuals/landing.htm

[bobodu]

It would be helpful NOT TO bury updates in older comments...

[KE4AVB]

Bob, you notice that too...Wasn't there when I replied to the question about the crankshaft earlier.

For those interested these solenoids can be cleaned most times using an ultrasonic cleaner and made operational again. They fill crud over time and stick in the extended position. I have cleaned over 20 these since I got may ultrasonic cleaner using just water with soap and it sure beats buying new ones. Just got gently blow out the water mix from them when your though cleaning. There no real reason to destroy these when they only need cleaning. There will be some that fail otherwise that is just the nature of things.

BTW I have been very please with the cleaner and have since quit using the soak method completely except in extreme cases. I am planning buying a larger, more powerful unit this year.