Small Engines (Lawn Mowers, etc.): B&S 22.5 Idle Adjustment, gold screw, silver screw

Question
QUESTION: My B&S carberator just got rebuilt. I'm trying to set the idle screws and having a problem. I have a gold screw and silver screw. The gold screw goes into the carb itself, the silver screw goes onto the throttle linkage. These are the only two adjustable items. How should I go about adjusting these two screws?

Thanks,
Timothy

ANSWER: The one on the linkage likely adjusts the low rpms, and the other one is only the low mixture.  When the low rpms are where you want it to be, you adjust the other needle until the engine runs smoothly,
turn to the left richens the mixture.

   What problems are you having?  Let me know, and also find the
engine's model numbers so I know what you have, and can give you more
detail,
Thanks,
Fish

---------- FOLLOW-UP ----------

QUESTION: Correction:  The motor is a Kohler. Model CV225 Spec 67515.

The original problem was a surging when there wasn't a sufficient load on the motor. If I ran with the blades engaged at high speed, it worked fine. Tooling around the yard it wanted to surge. Research showed rebuilding the carb would fix the problem. Which it seems to have done so far.

The problem I'm having now is getting the idle set correctly. The low rpm screw and low mixture were both part of the rebuild kit. All parts were put on that were took off.

Thanks for you help.
Timothy

ANSWER: Go here for an illustrated parts blowup, to make sure that everything is in the right place.

http://www.milacalawn.com/parts.asp

I am not sure what trouble you are having, when you idle the throttle down, it does what?

Does it not slow down?  It dies?  Runs rough?  Runs too slow?

---------- FOLLOW-UP ----------

QUESTION: I'm unable to get the same idle I had before the rebuild. Before, there was a wide variation to the idle. There was a definite high and low idle. Now, the mower will run; however, when I move the throttle lever, I get very little variation between the high and low idle. If I adjust Idle Adjusting Screw (22) just above the threshold of stalling at low idle, where the engine runs even, then I don't have enough rpm's at high idle to move the tractor much less running the mowing deck. When I adjust the screw just high enough to drive around and run the mower at high idle, then I can't get it to idle down. The Throttle Adjusting Screw (24) doesn't appear to do anything though I'm sure it has a function.

According to the diagram (Kohler, Command Series, CV22, 67515, Fuel System), it appears it's put back together correctly. I've done engine repairs on a few things before, I take extra care to make note of how things come apart and put back together. Of course, I've been wrong before. :)

Thank you so much for your time. :)

Timothy


Answer
It sounds like the low side is OK, but the high side is out of adjustment somehow, you need to adjust the throttle cable or whatever
you changed, so that when it is set on full throttle, it runs at 3600 rpm, then worry about the low idle setting.  Loosen the cable clamp, and pull back the cable as far as it will go, then retighten,
and see if the engine runs full speed.
  That is what your first goal should be anyway, as the mower should only operate at full rpm anyway.
  Try to get there, and let me know what you find out.


   Fish