Kohler 23hp stuttering

[fmints]

Hello Gents, I recently finished rebuilding my Kohler 23hp. It idles and runs great except when you occasionally hammer on the throttle, it stutters like its getting too much fuel (flooding). The air cleaner is clean and good. Im only running the factory mechanical fuel pump mounted on the valve cover. I pulled the plugs and they are indeed wet with fuel. Ok so I found the problem, so I think! So next, I look to the manual for the fuel mixture screw, I think I found it, but when I look at the carb,,, I dont see it. I would really hate to tear this thing all the way down again for a simple fix. My question,,, Where is the fuel mixture screw? What side of the carb is it on. What else will make it run rich on the top end when the RPM's are up (3400-4000 rpm's)? Any suggestions?

Here are pics of the carb on all four sides:



2012-06-21195547.jpg picture by fmints - Photobucket
2012-06-21195547.jpg picture by fmints - Photobucket

[crashingone2002]

dont know about kohler, but i have seen briggs hide the air mixture screw by putting a plastic cap into the bore of the screwhole covering the screw.

[fmints]

dont know about kohler, but i have seen briggs hide the air mixture screw by putting a plastic cap into the bore of the screwhole covering the screw.

That's great info,, I'll Check tomorrow!

[Mike]

One other thing to try before you start adjusting the mixture: Unbolt the 90 degree elbow on the carburetor and run it without anything there at all and see if it still stutters.

[Bazooo guy]

Drain the tank and start with fresh fuel.
Make sure the lines and filter are not leaking.
Check that you have good flow from the pump.
The fuel mixture shouldnt change....ignition could be breaking down at high rpm.

[jpswift1]

Drain the tank and start with fresh fuel.
Make sure the lines and filter are not leaking.
Check that you have good flow from the pump.
The fuel mixture shouldnt change....ignition could be breaking down at high rpm.

Possibly an issue with the coils?

[Dwayne]

Hi I will post you a post a comment I made about a similar problem the only way to try it is un bolt exhaust . The first symptom is motor running rich when you are full throttle Hi sounds like you having frustrating time .I fill like a goose but this is what happend what makes it worse is I build race engines for motor bikes. My max11 was brand new 2011model kolar 23hp had done about 120 hrs motor started running a bit strange lacking power then sort of come good but slowly got worse started flooding run alright with air filter off then wouldn't rev up with it on started spitting fuel out top of carby so the problem slowly got worse . So I pull motor down looking for sticky hydraulic lifters or brooken decompresser on cam witch I found they don't have .put motor back together problems stile there then a thought took off exhurst presto runs like a beauty .Cut exhurst open to stupid plates spot welded come lose block up exhurst well I fill like a goose with four other mechanics trying to figure it out .Give this a try you may be surprised

[fmints]

Bazoo Guy: There is new fuel lines and filter, and I cleaned the tank,,, which was done between FEB and APR this year. I also have an additional electric fuel pump, and the problem still persist even with the electric pump on.

Mike: The 90 degree elbow is stock, but i will remove it since this motor's previous application didnt have a need for high rpm's. So you think that its not getting enough air?

JP: I hope its not a coil, it could be,,,, but if it is why is there fuel on the plugs?,,,,, Oh,, the fuel not being fired. I'll have to test the coil then!

Dwayne: The exhaust,,,,,,,,,,,, there is a section of about 3 inches that the size is reduced in a 90 degree curve on both heads. So maybe those sections is not allowing the exhaust to exit quick enough and the fuel is being stock piled in the cylinder, thus running rich, stuttering and hesitating (wet plugs).

[Bazooo guy]

If it has points they could be worn, pitted, or not gapped properly.
If the exhaust is too restricted it will cause the valves to float at higher rpm.
Did you change the exhaust recently?
I found a mouse nest in my lawn tractor exhaust one spring....ran like crap till the grass caught on fire and blew out the muffler.

[jpswift1]

The Kohler Commands and Briggs Vanguards don't use a points/condensers, but messing with engines that have points/condensers, I know just what you mean.

[fmints]

If it has points they could be worn, pitted, or not gapped properly.
If the exhaust is too restricted it will cause the valves to float at higher rpm.
Did you change the exhaust recently?
I found a mouse nest in my lawn tractor exhaust one spring....ran like crap till the grass caught on fire and blew out the muffler.

I think that this could be the problem, because it only happenes at higher rpm's, or when i put the hammer on the throttle, which is all the time! Well, come saturday morning, i'll be drawing up yet another exhaust, checking air flow, and testing my coil. Thanks guys for the advice, i'll keep you posted!

[highrollinmopars]

How did that work out for you? Does that axle fit?

[fmints]

How did that work out for you? Does that axle fit?

YEAH BUDDY, the axle fits, i slapped it in yesterday. THANKS A MILLION "HIGH" for supplying me the axle. Your a swell, honest dude!!

Also, the stuttering problem,,,,,,,, after fumbling with the carb all day yesterday, along with flipping the tires this way and that way, running back and forth to O'riellys for axle bolts,,,,, I finally found the problem. I went back into the carb and throughly cleaned the carb again,,, which was useless because it was just cleaned like a month ago. I noticed when putting the carb back on the intake that the choke lever, controlling the opening and closing of the choke, was opening when i increased throttle,,,,,,,,, flooding the heck out of the 23hp, and robbing it of power, sputtering and stuttering. So i just rigged up. Took off the choke cable and rod, and tied some wire to the choke lever to the engine to keep the choke in an open position,,,,,,,,,,, Wicked throttle response now, and 3 times more power than before. It still stutters when going up really steep hills, but that's to be expected i guess with the fuel level and float in the carb (even with the electric fuel pump on,,,,,,, i'll figure it out).

[fmints]

Ok, so since my last post, i have went through numerous things trying to correct the stuttering issue with my engine. i have replaced the head gaskets, intake and exhaust gaskets, spark plugs with correct gapping and lapped the valves for an air, liquid, and light tight seal. These things made the 23hp Kohler run better but still the stuttering issue remained. it wasnt until Cbass and I put our heads together when Cory suggested that i didn't have any back pressure on the my exhaust. i bought two mufflers meant for 9-12hp lawm mower engine last thursday and yesterday welded everything in place... the problem was solved. Smooth acceleration thru the rpms and not stuttering,, quick hand fulls of throttle throughout the powerband raising the rpm's,,, and still no stuttering, with and without load. The last exhaust that i built, flowed too well, causing the engine to take on too much fuel and flooding, hence the severve stuttering and backfiring.

I have some exhaust tips that should come in today from WWW.BMIKART.COM, and some header wrap on the whole exhaust should wrap up the project. later i will fabricate an exhaust duct to help channel the heat out of the tub. I also have a 12 inch fan, but I fear that it would draw too much juice and drain my battery in the long run. I wish i had purchased the 7inch fan instead. Bigger is not alway better.

So in this case problem solved.

[jpswift1]

Glad to hear everything worked out for you, Fred. It seemed like quite the issue, but now we know. I was thinking about making my own free flowing exhaust set up for the Kohler 23HP Command that's going in my Swamp Fox, but I'll certainly be steering away from that and just going with a factory muffler on it to prevent any problems.