Newly rebuilt K241

[tranders 0]

Just rebuilt the K241 in my brother's Raider10. Problem I'm having is every 10 to 15 seconds it has a slight stumble. Not one I can feel,but hear through the exhaust. This is what I've done so far. Fresh rebuild,new points and condenser set at .020,rebuilt carb, valves adjusted per the Kohler manuel,new spark plug set at .025. At this point the only thing I haven't replaced is the coil and coil wire.

Any ideas would be appreciated.

Thanks!

[rmaynard 15,788]

Your title says newly rebuilt, but the things that you said you did indicate that you just did a tune-up.

Was it a rebuild or just tune-up? A rebuild would mean cylinder bore, new piston & rings, valves, and possible crankshaft turn with new rod, or any of the above.

Did you rebuild the carburetor?

A few more details may give us a clue as to what your problem is.

Bob

[tranders 0]

Yes complete rebuild.

Block was bored .020 and crank was polished. New piston and rings and rod. Valves were also ground and carb was rebuilt.

Sorry for the poor explanation.

[rickv1957 72]

Maybe needs a slight adjustment on carb fuel mixture,Rick

[rmaynard 15,788]

Are you hearing the "stumble" with the muffler on or off, air cleaner on or off? At idle, full throttle or anywhere in between?

[tranders 0]

The only time I get the stumble is at full throttle with muffler and air cleaner on the engine.

I have adjusted the carb numerous times with no affect.

The pepper shaker muffler is brand new as well as the air cleaner.

The stumble is not really a power loss,but it's audible.

[Audioshot 2]

Sounds like the air/fuel mixture screws need slight tweaking. Mine did something like that in the mid throttle range and I had to play with the main jet a tad.

[stevasaurus 22,962]

It is possible the governor linkage could need a tweak. At full throttle the "stumble" could be a little surge. :thumbs:

[rmaynard 15,788]

The only time I get the stumble is at full throttle with muffler and air cleaner on the engine.

I have adjusted the carb numerous times with no affect.

The pepper shaker muffler is brand new as well as the air cleaner.

The stumble is not really a power loss,but it's audible.

Is the problem when you are moving or sitting still?

Bob

[gwgdog66 23]

Is this a battery type ignition system? If so double check the spark plug gap. Some Spec Kohler's call for a .035 gap.

To me is sounds like a carb adjustment issue still. Get the Engine warm and fine tune the high speed screw. It needs to be under load to fine tune it.

On mine I engaged the mower deck.

[tranders 0]

The problem occurs while sitting still and moving. Going to check the governor linkage. Possibly change location of spring?

[rmaynard 15,788]

The problem occurs while sitting still and moving. Going to check the governor linkage. Possibly change location of spring?

I set mine to 3 up from bottom on the governor arm and 3 down from the top on the throttle arm. That helped while driving, but sitting still, the governor has no effect. It only comes into play when the engine is under load and you start to lose speed. Then the governor kicks in causing the throttle to open more keeping speed consistent.

I would be more inclined to think it was carburetor or ignition related. Take the main needle valve out and re-clean it. The entire tube from one end to the other is hollow, and needs to be clean. Soak it over night in carb cleaner, or lacquer thinner. Since it is difficult to get anything like a fine wire inside the tube to clean it, you have to let the cleaner soak it out. Then try to block all the holes but one at one end, and force air through the tube to blow the debris out the the holes in the other end. Once you are sure that the tube and all the holes are clean, readjust it per the manual.

Bob

[tranders 0]

Will do Bob.

Thanks for the help.