Kohler 2 cyle 5 HP engine carburator adjustment

86 911 · 86 911's Garage

I have a Kohler 5 HP carburated engine with a carburetor that needs adjusting. What is the setting of the carburetor?
When we start the motor it will idle for a few minutes then quit.
We try giving it gas and it chokes up and dies. We attempt to run the motor with the choke part way on and the motor will run for about 1 minute before quitting. The spark plug is dry and heavily fouled.
The engine had been setting for a couple of years. We reseated the valves and cleaned out the carburetor, added new oil and gasoline. The P.O. had said that the carburetor was new and used for only an hour.

Any suggestions and what is the proper initial setting for the low idle jet and the high speed jet?

Here's a photo of the engine:

yellowline · 03:36 PM

A spark plug will set you back $3 or less, yet it's one of the most important parts of a small engine. Get one, they're not hard to find. On 2-strokes, they foul easily, too. You need a new plug for it to run properly. No clue on carb settings, though. If you had a Briggs flathead, I could tell you.

This isn't official, but once you get a plug, I'd try starting it (without the chain attached), run it at about 3/4 throttle, and adjust the high speed jet until it doesn't sputter. Then idle it to adjust the low speed jet.

You know, there are a couple steps between a 911 and a go kart. Like a 944 or 914.

86 911 · 86 911's Garage

LOL. Actually the plug (CJ8) is new as well. I went out and bought one a week ago. I could go ahead and sand-blast it, but I would like to get the correct mixture first.

turbo6bar · 08-07-2005, 03:54 PM

If I'm not mistaken, it's 1 turn out on the idle and main jet.

When I'm tuning small engines or chainsaws, get the machine running on the idle circuit (x turns out from seated). Back out the idle screw until it stumbles, and then back in 1/8 turn. Then, blip the throttle. If it doesn't respond immediately, lean out the mixture. On main jet, adjust while under load.

turbo6bar · 08-07-2005, 03:55 PM

BTW, is that really a 2 stroke engine?

86 911 · 86 911's Garage

Yes, it is a 2 stroke. Thanks for the info Turbo6bar. We've tried adjusting it as you said, but it just dies like there is no fuel supply. Although the carb is basically new, the engine has been setting outside in the weather for at least 2 years. Any suggestions on where to troubleshoot?

turbo6bar · 08-07-2005, 05:16 PM

Are you positive the idle and main circuits are functioning? Float bowl working properly? When the engines dies, can you bring it back with a squirt of starting fluid?

dhoward · dhoward's Garage

Take that little carby apart and hit it with some carb cleaner. Make sure you get it into all of the passages. Check the needle seat. Sometimes they swell. Make sure the float moves freely.
Based on where the plug is in that head, it really looks like a 4 stroke....
Start 1 1/2 turns out on all of the screws.
After looking at it further, that REALLY looks like a 4 stroke. If the plug is dirty, but not wet, you're not getting fuel.

turbo6bar · 08-07-2005, 06:13 PM

I think he might have a clogged idle circuit. Does the engine idle smoothly? It may be running on the main.

1.5 turns on the main. 1 turn on the idle.
http://www.small-engines.com/preform.html

yellowline · 06:48 PM

I agree, old cast-iron Kohlers and Briggs that look like that are 4-strokes. Hope you haven't run too much gas/oil mixture through it until you get the numbers off the engine and figure out exactly what it is. I actually ran a Briggs on a tankful of diesel once...

Do this at your own risk...If it isn't starting well, remove the filter, pour A LITTLE gas (meaning not even a full ounce) down the air intake, pull the starter, and see what happens...again, do so at your own risk though, and make sure no other people or combustibles are nearby. That should help tell you if you've got dirty passages in the carb.

86 911 · 86 911's Garage

Thanks. I took the carb apart and cleaned out all of the circuits. 2 of them were clogged. I then started the engine and it idled and ran fine when cold, but then when it reached operating temperature (about 10 minutes), the engine starts skipping and dying when you apply the gas pedal.

Tim Hancock · 08-08-2005, 04:05 AM

That is not a 2-stroke, which should be obvious as you stated you reseated the valves. Make sure your timing/points are OK also. Sometimes these engines will shear the key on the flywheel which botches the timing. Most likely you just need to adjust the high speed mixture if it is running ok at idle. Once warmed up, the engine requires a leaner mixture than when initially starting so turning the main in slightly should do it.

86 911 · 86 911's Garage

Thanks guys. Tim and yellowline, you are correct, it is a 4 stroke. The problem has been fixed. All it was, was the timing. We adjusted it to the setting on the Kohler manual, but it tuned out to be a different timing setting. Overall, the engine needed a coil, condensor, points, drive chain, spark plug, and some tweaking. Not bad for sitting out in the weather for at least 3 years. Some gasoline is seeping into the oil, but as long as the oil is changed often, it shouldn't cause too much of a problem.