Kohler CV730S-0029 Nikki Carburetor Problem

Howdy all. 25HP Kohler in a Craftsman GT5000 rider. This mower had been sitting a couple of years before I bought it. This is what I did before attempting to start engine, removed air filter, removed plugs and verified spark on both sides, noticed plugs where very a dark brown, checked compression, 165 psi + on both sides, put a gallon of gas with 1 oz of seam foam in tank and fired her up. Started within 5 or so seconds with choke on. Pushed choke back in and let her idle for a few minutes. After warming up I took her for at test drive. Started surging right away and had to keep the choke about 1/2 way to keep it running. At this time I sprayed carb cleaner all around intake and carb to determine an intake leak and found none. Removed Nikki Carb and disassembled, it wasn't all gunked up and pretty clean looking. Went ahead with cleaning all the passages with small copper wire, carb cleaner and compressed air. Reassembled, installed and another test run. Started easy enough, and no surging this time. However, from idle to full throttle it bogged the engine down, like to much fuel. At this time I verified that the choke was operating properly and ruled that out. I had my son go from idle to full throttle while I watched the carb. I can see gas vapor coming out the carb intake while doing this. Definitely to much in my opinion. If I slowly increase throttle from idle to full it won't bog down and seems to run good. Also when I engage the PTO at full throttle it will bog the engine down and die, but if I engage it at half throttle and slowly increase throttle to full it'll keep running and mow like it should. If anyone can point me in the right direction to fix this problem, please do. Thanks again ya'll

Make sure the fuel solenoid is working properly and that the plunger is not hanging up due to crud behind the plunger, If that works out OK, What you are describing with the falling on its face may be due to either the accelerator pump isn't working or your carb doesn't have one.

what is happening is the sudden acceleration causes the carb butterfly to open suddenly, and there isn't enough fuel available to overcome the additional load and dies. Suddenly moving the throttle can do the same thing as turning on the pto.

Thanks for quick reply:thumbsup: I can hear/feel fuel solenoid clicking when cycling the key on/off. It has the accelerator pump and I'm thinking that the diaphragm has a pin hole in it thus allowing the carb to suck excess gas. I plan on removing carb again to check diaphragm and solenoid operation. I'll let you know what I find. Thanks again

Update on this. Went ahead and ordered both gasket kits, re-cleaned everything and re-installed. Started er up and bingo, problems solved. Runs great with plenty of power. Thanks again all :thumbsup: