Messed up low idle adjustment

Kohler Courage SV610-0212. New Spark Plug set to recommended gap, Fresh Oil, Oil Filter, New Air Filters, Running rough. I adjusted the low idel screw and got it running smoother, but wanted to set the low idle speed to 1500 rpm. got a no-contact digital tachometer, and it registered high. I turned the screw further clockwise, and egning is running rough at all speeds again. I did not hae enough weight to put in the seat while I turned the adjustment screw. Is there a starting point that I should turn the screw to, such as midway between the stops, in order to be able to set it properly, or should I just follow the instructions in the repair manual, which I have downloaded to my computer?

Sounds like that carb needs to come off and have a little rubbety dub dub.
You should be able to run the engine without an operator in the seat if the parking brake ia applied.
If not then the safety switches need some work

Actually, the carburetor is very clean. I've already checked that. I didn't think about applying the parking brake. Ill try that out next, once the rain gets out of here. Don't like fumes and smoke in my shed. Thanks for the suggestion.

Now there are two idle adjustments.
One simply limits how far the throttle butterfly can close
The other changes the air : fuel ratio which on most modern carbs is blocked off.
If you are working with the latter yo should only be able to turn the screw 1/4 turn in either direction without the engine dieing.

bertsmobile1 said:

Now there are two idle adjustments.
One simply limits how far the throttle butterfly can close
The other changes the air : fuel ratio which on most modern carbs is blocked off.
If you are working with the latter yo should only be able to turn the screw 1/4 turn in either direction without the engine dieing.

Click to expand...

The one I'm working with is the Low Idle adjustment screw that sits on top of the carb parallel to the engine block. It is accessible from the front , but with the air filter housing in place, it is a little tricky to actually see what you are doing. Taking the housing off to totally exposes the screw allows too much air into the mix, and the engine runs really rough, which makes it difficult to properly adjust. I don't have a picture of it at the moment, or I would copy and paste it here.

MShan said:

The one I'm working with is the Low Idle adjustment screw that sits on top of the carb parallel to the engine block. It is accessible from the front , but with the air filter housing in place, it is a little tricky to actually see what you are doing. Taking the housing off to totally exposes the screw allows too much air into the mix, and the engine runs really rough, which makes it difficult to properly adjust. I don't have a picture of it at the moment, or I would copy and paste it here.

Click to expand...

You do not adjust the speed with the mixture screw,
You turn it one way til the engine starts to faulter then turn it the other way til the engine begine to faulter then set it 1/2 between the two erring always to the rich side,
You adjust the speed with the throttle stop, closing down the throttle till you get to the speed you are looking for.
Once there you adjust the mixture screw again the exact same way , after which the engine usually runs a little quicker so you adjust the throttle stop.
This process gets carried on at infinitum till you have a smooth idle at the desired speed.
When properly adjusted a mixture screw should be very sensative and only allow th engine to run over a range of 1/2 to a 1/4 turn.
If not then the throttle stop is still too far open and you are still running partially on the main jet.
If you get little to no difference to turning the idle mixture screw at anything under 2000 rpm the the idle passages are blocked or the screw is damaged.

In my foggy memory I think I remember it is possible to over torque the little screw which usually has a pointed tip and can enlarge (reform) the mixture screw seat. I hope that has not happened. Very light touch required.