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Hot!Help...Kohler Command 20 Running Rough

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abeckler
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2018/12/24 02:04:40 (permalink)
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Help...Kohler Command 20 Running Rough

Hey guys I’m new to the forum so I hope I’m posting in the right spot.
I bought a Lincoln Ranger 8 Welder Generator with the Kohler CH20S Engine. It only has 61 hours on it, when I bought it the owner said it had just been sitting in the back of a shop and hadn’t been run in 7 years. So I drained the tank completely and “rebuilt” the Keihin Carburetor with a new o-ring and gasket set and cleaned it out. Put a can of sea foam in the tank and got it to start running. It runs rough and super rich. Sounds like it might have a knock, but it only does it every once in a while... I got a new air filter and changed the oil with Royal Purple full synthetic 10w-30. New fuel filter. No changes what so ever. Changed the spark plugs and they were carbon fouled pretty bad. It sounds like the engine is missing. And I noticed that if I pull the spark plug wire on the cylinder opposite of the starter, the engine smooths out and sounds like it’s running great. So I thought it may be a spark issue. I replaced the ignition coil on that side with no change, I rewired the coils all the way back to the ignition switch thinking it may be a wiring issue. I used steel wool on the mounting surfaces for the coils thinking it could also be a grounding issue and also ran an auxiliary grounding wire... still no change. The good cylinder has 175psi of compression and the side that is missing has 172psi... so I'm completely at a loss. I’ve also tested for a leak on the intake gasket with no luck.... I’ve read that it could possibly be a blown head gasket but I don’t see how that could be it with only 61 hours.... maybe a valve issue? But I pulled the valve covers and roatated the engine and they’re opening and closing as they should be. My only other thought is possibly a timing issue? Maybe the magnet on the flywheel got bumped and moved somehow? I really don’t want to take the damn thing into a shop... any input, advice or solutions would be greatly appreciated! Sorry for the long post. I just wanted to get everything out there that I could.

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    AVB
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 09:02:22 (permalink)
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    We could stand to have the spec number but I am assuming you the fixed CDI ignition though the are two other ignition systems possibly used. I just look at the first CH20 listed for the Miller welder and I have no idea what Lincoln used.
     
    Sounds like you still have a carburetor issue as it is running rich which will cause misfires. When you said you cleaned out the carb, how did you clean it?
     
    The knock can be only a some loose carbon in the cylinder if you are lucky or you could have a valve seat that is loose that is randomly jamming the valve closure. The only way other than an inspection cam (camera) to see what going on is to pull the head. Even with an inspection cam valve seat problem may not be seen. Now a loose valve seat can cause misfires too.
    post edited by AVB - 2018/12/26 04:14:42
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 14:33:06 (permalink)
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    Spec. Number is 64683
    Serial Number 3304207611
    Yes I have the fixed timing. It does not have the Smark Spark system.
    I cleaned the carb out with a small wire brush in the bowl and where I could get with the wire brush. Cleaned out all of the small Orifices with Carb cleaner, compressed air and a guitar string. I guess it could be a valve seat sticking. But I pulled the valve covers and just by looking at the valve springs and rocker arms they seem to be opening and closing properly as they should so that leads me to believe that they’re not sticking. But I could be completely mistaken.
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 14:38:35 (permalink)
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    I’ve also adjusted the float multiple times, because I thought the float may be sticking open or the needle valve not seating properly. But the reason that leads me to believe that it has to do with just the one cylinder is that when I pull the spark plug on the “affected” side the engine runs smooth and no longer runs rich... which makes absolutely no sense. So I’m at a loss... I thought it was a spark issue but I replaced the coil on that side as well as swapping the coil from the opposite side onto the affected cylinder with no change. The coil has power and the spark plug when pulled has a visual spark... so again I’m confused
    Roy
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 16:32:28 (permalink)
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    Does it smooth out when you pull the other plug wire? AVB, I am not familiar with Kohler v-twins, do they have a diode system like Briggs and Stratton?
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 16:50:42 (permalink)
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    When I pull the plug wire on the “bad” side it smooths out. When I pull the plug wire on the “good” side it sounds the same if not worse.
    AVB
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    Re: Help...Kohler Command 20 Running Rough 2018/12/24 17:32:44 (permalink)
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    Roy
    Does it smooth out when you pull the other plug wire? AVB, I am not familiar with Kohler v-twins, do they have a diode system like Briggs and Stratton?

    Yes they diodes but they are internal to the coil pack therefore are not replaceable like Briggs. They however behave the same way by shorting, opening, or becoming leaky. I a twin earlier that would only run with one or both coil's kill terminal disconnected. Both coils had shorted the diodes therefore was killing each other.
     
    One thing that can be tried to see if its the coil that the OP hasn't changed is to swap them around and see if the problem moves to the other cylinder.
    post edited by AVB - 2018/12/24 17:35:26
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/25 18:25:59 (permalink)
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    I’ve tried swapping the coil to the opposite side with no change. And acts the same where at low idle or under load.
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/25 18:42:00 (permalink)
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    https://youtu.be/5AbFFq6ovCc
    Roy
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    Re: Help...Kohler Command 20 Running Rough 2018/12/25 23:56:50 (permalink)
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    That tells me the problem is not ignition related. The compression readings sound high which means acr is not working, are the valves properly adjusted? Is it a 2 barrel carburetor? Maybe there is a problem in the circuit feeding the bad cylinder.
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/26 00:11:55 (permalink)
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    Per the manual for the engine, it says compression should be “at least” 160 psi but also states that the engines are hard to get an accurate reading due to them being equipped with an automatic compression release. But that makes me think the readings should have been lower then?? It’s a single barrel carb. And what do you mean by a problem in the circuit??
    AVB
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    Re: Help...Kohler Command 20 Running Rough 2018/12/26 04:23:09 (permalink)
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    This engine does not have an ACR on the camshaft as hydraulic lifters are used and an ACR wouldn't work even if it was present as the lifters leak down while sitting. This is misinformation in the service manual as the writer assumed all engines have a mechanical ACR.
     
    What I believe Roy is referring to as circuit problem is metering circuits in the carburetor but being a single barrel that would affect both cylinders.
     
    With the problem not moving when you swapped the coils around says it is definitely related to cylinder that is acting up. As I said before it could be a loose valve seat but only pulling the head can verify if there is an internal problem in that cylinder. It could be rod or valve guide related too. I have seen valve guides to move on these engines. Either way I feel you are in for an engine tear down to do the inspections.
    abeckler
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    Re: Help...Kohler Command 20 Running Rough 2018/12/26 22:06:22 (permalink)
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    Hey just wanted to thank everyone for their input! I finally got it figured out today and it’s running great now! It ended up being the carb. I guess me cleaning it the first time didn’t fully get the job done. I ended up going and getting the ultrasonic cleaner from harbor freight and drilling out the cap over the idle fuel adjustment needle and the needle was all gummed up. So I cleaned it and put it back together and it’s a world of a difference!
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