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Kohler CH22 engine speed hunts


John4901's Avatar
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12-18-13, 08:30 AM   #1  
Kohler CH22 engine speed hunts

I have a Kohler Command CH22 engine. On a small Vermeer chipper BC625. Sat for 4 yrs. Water in gas. I have drained tank, new gas, new filter. Removed carb, had water contamination.

I bought Kohler rebuild kit and rebuild seemed to go well. I am handy but no expert on rebuilding carbs. Soaked two main pieces overnight in lacquer thinner. Cleaned all little openings, etc. Installed kit. Reinstalled on engine.

Engine now starts immediately with choke. Throttle set at idle. No load on engine. Starts speed hunting from slow, almost dying, to medium fast. Adjustment of idle mixture doesn't do anything. Runs same with idle adjust completely closed. Gas is coming from a little tube in carb that projects from side of throat. Throttle stays against idle speed adjust screw.

Ideas? Thanks. John.

 
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Pilot Dane's Avatar
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12-18-13, 08:57 AM   #2  
I am guessing the carburetor needs more work. Possibly in the idle circuit especially since you say adjusting it has no affect. At idle the throttle plate is closed so most of the fuel comes from the idle circuit. If it's not providing fuel then the engine starts to die, the governor opens the throttle and the high speed jet provides fuel, engine speeds up, governor closes the throttle and the cycle keeps repeating.

When you say gas is coming from a tube does that mean fuel is dribbling out of the carb and onto the ground or you see a tube dispensing fuel into the throat of the carb?

 
John4901's Avatar
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12-18-13, 12:01 PM   #3  
There is a small tube, about 3/4" long, sticking out of side of throat, about 1/2" into throat. When I have engine running I see gas kinda spritzing out from. I think that is where the gas is coming from that is running the engine (rather than idle mix). What you say makes sense re more work on carb, but I took it apart this AM and didn't see anything wrong. I removed idle mix screw, hole/seat looks clean and open.

 
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12-18-13, 12:04 PM   #4  
One other thing I should mention. When speed is surging (idle position on throttle), the throttle is staying against the idle. The governor is not moving the throttle.

 
cheese's Avatar
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12-18-13, 04:59 PM   #5  
Sounds like your idle circuit is partially blocked. Lacquer thinner isn't really suitable for carburetor cleaner. I'd recommend soaking it in real carburetor cleaner designed to dissolve the varnish and buildup left by old gas.


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