kohler magnum 18, running funny

[vladhimself]

maybe you guys can help me. i've done numerous searches and this site keeps popping up. i have an old kohler magnum 18 engine, horizontal shaft. it runs ok but it acts like it wants to die like it's not getting enough gas. it doesn't die but it revs up then slows down, revs up and slows down. the only thing i could think of would be that is needs a bigger fuel line, carb rebuild or fuel pump. any other ideas?? thanks.

- Ryan

[Restrorob]

Ryan,

Give this a try;

Start the engine and set the throttle where the rpm's go up and down, Now slowly apply the choke and see if the engine smooths out at any given choke position.

If it does the high speed circuit inside the carb is restricted;

Take the carb. off then tear it down, Spray carb. & choke cleaner with the straw through ALL ports, passages and jets then blow it out with compressed air if available then re-assemble, Check/clean the fuel tank and flush/replace the fuel hose and install a new fuel filter.

If the engine doesn't smooth out applying the choke it may be time to check/adjust the governor.

[dutch1]

Do as Rob indicates, then if it occurs again in a few hours check the fuel pump, particularly if there a tiny fibrous debris in the carb bowl.

I recently worked on an 85 wheel horse that the owner had been having some running problems. It would run for a half hour, then die and again restart after a short rest. I went through the carb, noting some small fibrous debris in the carb bowl. Drained and blew out tank, replaced filter and fuel lines. I set it outside to run for 30 minutes, called the owner to come and pick up.

Three or four days went by and the gentleman called me to let me know that it was acting as it was before. Again there were the fibrous pieces in the carb bowl as well as piece lodged in the emulsion tube. Since I was aware that everything was clean, the problem had to be in the fuel pump. I removed the fuel pump, disassembled it to find one of the check valves out of its port and a large piece of the fibrous washer that had been under the check valve loose in the pump. The metal portion of the diagphram had been slowly beating on and breaking up the washer then passing it on to the carb.

Looking back, it would have been advisable to go ahead and pull the fuel pump the first time through. Oh, to get so smart so slow.

Dutch

[vladhimself]

well guys, i bought a new fuel pump for it. it was definitely time for a new fuel pump. when i took it apart it was all corroded inside and i'm surprised that it was getting any fuel at all the way it was. i also rebuilt the carb on it today. it's not getting any fuel. i have clear lines on it right now so i can see the fuel. i must have done something wrong rebuilding it? i don't think so though... i replaced exactly the parts it gave me and cleaned it thoroughly. the needle that i took out is the same needle it gave me in the rebuild kit. the only difference was that the new needle i got with the kit has a tiny spring on the head of it. there was no spring on the old one. i don't now if it got corroded and desolved itself or what. i put the new needle on it as i got it and the float sat a little funny. like the spring was pushing it up a bit. i don't now if thats normal or if the float is supposed to be sitting flush? should i take the little spring off the top of the needle?
i'm going to mess with it tomorrow, but if i can't figure it out i would like some feed back before then so i can get it running right tomorrow. thanks guys.