Throttle Shaft Play

[MalMac 1,328]

On the Kohler carbs, what's the best method to use in determining if throttle shaft too much wear. I have got a couple if carbs here that no matter how much adj. I do I just can not get a smooth runner. You can move the shafts ever so slightly which indicates some wear. Tried spraying carb cleaner around them without much effect. Both engines run strong but each have that stutter or intermittent sputter.

[rmaynard 14,906]

I would first be suspicious of a partially clogged main jet needle valve. The long one on the top. It is hollow and has several tiny holes. All holes must be open, and the inside of the tube must be clean and able to past air between all the holes. After that, the ports inside the body of the carb may be partially clogged (darned ethanol gas). A good overnight soak in carb cleaner or lacquer thinner will help that problem Then the last thing I'd look at is the throttle shaft. I can't tell you how much wear is a problem, but a new kit is a cheap way to find out if the problem goes away.

 

Here is where I get mine.  http://www.mowers4u.com/kohler-kohler-carburetor-throttle-shaft-bushing-p-873.html

 

Having said that, I recently had problems with the carburetor on my B-100 doing the same thing. I installed a rebuilt carb that had a throttle bushing kit and still had problems. So I spent $75.00 and bought an imported after-market one off eBay. Bolted it on and without any adjustments it ran perfect.

[MalMac 1,328]

Everything was soaked and cleaned. Guess I am just down to a sloppy shaft. Not sure what else it would be. Even replaced the needles. I did check to see if I had a leaky manifold gasket. Everything seemed fine. Wondering if the crappy gas over time has just messed with all the small passages.

[tunahead72 2,342]

... Here is where I get mine.  http://www.mowers4u.com/kohler-kohler-carburetor-throttle-shaft-bushing-p-873.html ...

 

 

Bob, that's a great link, with a really nice description of the part, symptoms of a loose or worn shaft, and suggestions for installing a new one. Thanks for sharing!

[953 nut 51,734]

  Have you given Seafoam a try? If not, get a can of the spray carburetor cleaner, remove the air filter, run the engine at half throttle and spray into the air intake. Lots of smoke will come out, but by the time the can is half gone you should notice an improvement. Also, use some in the fuel tank as regular procedure.

 

​The process I have used to detect a bad throttle shaft is to put a couple of drops of gear oil around the shaft while running, it is thick enough to seal the gap without being sucked in.

 

Let us know how you do, good luck. 

[MalMac 1,328]

953 Nut, hey thanks for the gear oil tip. I'll give it a try.