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Engine Help => Kohler Engines => Topic started by: dropzone on March 19, 2014, 08:55:26 PM

Title: Ch20 v twin Carb problem
Post by: dropzone on March 19, 2014, 08:55:26 PM
I'm working on a Kohler Family 3KHXS.6242GC, Model CH20S, Spec 64510, S/N 3319007311. I am looking for a Carburetor that will fit other then the factory emission friendly carb. The carb on it is gummed up bad and I cant get it to run right. It idles fine and the high speed is good it's off idle that is giving me fits, I have soaked it over night 3 times, sprayed it out with carb cleaner and blown it out with high pressure air from my compressor each time. I even replaced all the seals and gaskets and slow idle needle valve so it's rebuilt. This isn't my first rodeo but for the life of me I cant get this thing to work like it should I think it is a loosing battle. The guy I got the motor from let it set for a few winters with un-treated gas and you guys know what happens. I'm looking for a non emissions carburetor that will fit if there is a alternative. I do have two good carburetors off a 18 hp Briggs opposed twin if you guys know of an adapter that will work would be nice also.
Title: Re: Ch20 v twin Carb problem
Post by: The Tank on March 20, 2014, 09:15:26 AM
Ultrasonic cleaner is the only true way to clean a carb. Not sure if it would fit or not but lots of guys are using the 2 barrel carbs from the 30hp Kohlers. You would also need the intake as well.
Title: Re: Ch20 v twin Carb problem
Post by: Cromwell C4 on March 20, 2014, 09:59:50 AM
I can hook you up with a new carb at a killer deal. I have the bigger carbs off the 25/27hp, and they will add a few extra HP. However, make sure it's a carb issue first. You could have a bad spark plug(s), a valve not seating, or an ignition problem. Do a compression test or a leak down test and see what you find there.
Title: Re: Ch20 v twin Carb problem
Post by: dropzone on March 20, 2014, 03:56:48 PM
I replaced the plugs twice and it has 155 - 160 psi both cylinders. I haven't done the leak down test yet. I did check the coils by pulling a wire at a time and it was the same on both. A leak down test will be my next step.
Title: Re: Ch20 v twin Carb problem
Post by: GRUBDIGGER on March 21, 2014, 07:22:31 PM
I replaced the plugs twice and it has 155 - 160 psi both cylinders. I haven't done the leak down test yet. I did check the coils by pulling a wire at a time and it was the same on both. A leak down test will be my next step.

RULE OF THUMB ON A KOHLER COMAND IS 165 MIN ON COMPRESSION. DO A LEAK DOWN AND A WATER MANOMETER TEST.
Title: Re: Ch20 v twin Carb problem
Post by: Cromwell C4 on March 21, 2014, 09:05:58 PM
Also do a check on the valve train. I've seen several motors wipe an exhaust lobe on the cam and not have enough lift to run properly. And make sure the hydraulic lifters aren't sticking causing a valve to stay open. Just a simple process of elimination  8)
Title: Re: Ch20 v twin Carb problem
Post by: dropzone on March 21, 2014, 09:16:37 PM
I think I found the problem it's a blown head gasket on the #2 cylinder. I didn't think anything about using a leak down tester thanks for reminding me. I suppose a tare down is in order. 
Title: Re: Ch20 v twin Carb problem
Post by: Cromwell C4 on March 21, 2014, 09:47:33 PM
Glad you found the issue. Let me know if you need anything. I have tons of new kohler parts in stock at or near dealer cost.
Title: Re: Ch20 v twin Carb problem
Post by: dropzone on March 22, 2014, 07:20:27 PM
Is it true that Kohler changed the head gaskets for these motors? Does any of you know the part number? I am going to tare it down completely so I will need all the gaskets.
Title: Re: Ch20 v twin Carb problem
Post by: Cromwell C4 on March 22, 2014, 08:24:49 PM
I know they changed the head gaskets on the 25/27hp 83mm bore engines. The new style are wider and have a built in steel fire ring. Not sure on the smaller engines though. The gaskets sets for the 18/20hp engines still come with the standard gaskets.