CH740 with a single barrel Keihin carb. Having issues with the return spring on the throttle plate. Seems like there is no spring pressure to close plate. Carb is off engine so no linkages affecting it. Purchased a new spring and while there was a difference from new to old it still seems like i can get the throttle plate to hang up and the spring is very slow to close the plate. Thought maybe the accelerator pump was hanging up causing this but it moves freely. Ive adjusted the plate using the mounting screws and no improvements.

Anyone have any suggestions on this or seen anything like it? Or better yet have a 27hp kohler and could see what kind of spring return their throttle plate has?

The governor arm dosent have return pressure until the engine is running. I hope your governer is working and all u need is to figure out how to adjust it

UPDATE ON THIS.

Adjust float in bowl back to factory specs. Found the correct OEM manual after speaking directly with kohler the manual I had was a misprint BOTH THE CROSS SHAFT AND GOV ARM ARE ADJUST COUNTER CLOCKWISE TO THEIR MAX.

Took the engine back out (its on a mud motor). Still does the same thing. Only this time it would run great for 30 or so seconds give or take. Die and then would only start when choked. AS it started it blew a puff of black smoke. So the engine is starving for fuel would be my best guess. Plugs looked a little on the lean side and that was evident by my mixture setting only being about 1 turn from seated. Exhaust still smells very rich to me which is odd.

From my tank (which I have removed the fuel cap during the test run to verify) i have a quick disconnect, old 5/16" fuel line to a primer bulb to a NON OEM fuel filter to the mechanical fuel pump to the carb.

Im planning to replace the disconnect with a barb fitting, new 1/4" fuel line, new bulb, new OEM fuel filter. Im going to test the output of fuel BEFORE replacing this and AFTER to see if there is any change in fuel flow rate.

IF there is no change in fuel rate last resort is a new carb.

Assuming this is my issue does anyone see anything I might be missing here? Im wondering now if my original issue wasnt starving for fuel and by choking it I caused the sooty plugs I saw before adjusting the carb float? Engine acted the same though run then die. under no load it still runs great, its only under a load (with increased fuel need) it dies within a short time frame. It will then only restart if choked.

FINAL UPDATE

Since I had so many replies to this I figured Id take the time to update the issue for anyone seeing this down the road.

Found two things that were contributing to the problem. The engine was starving for fuel. Did a test with the original fuel line (quick disconnect, 5/16 line, bulb, NON OEM filter, pump, line) and pulled the plugs and ran it for 10 secs into a bottle.

Then went to (barb fitting, new 1/4 line, new bulb, OEM filter, pump, new 1/4 line) and did the same test. Had 3 times the amount of fuel and no varnish present vs the original line.

Then in the carb the OEM fuel solenoid on the carb had rust on the actuator shaft causing it not to fully retract. This only effects the high speed circuit of the carb. A new solenoid was $150+, so after reading up on it. It was determined it is not needed and is only a backfire solenoid. You can clip off the shaft and reinstall. You just cant cut out out wide open and need to idle down to shut down to avoid backfires.

These two things solved my issues and runs like a bat out of hell now. Thanks Will for taking the time to reply to this.