Low Speed Roughness

Bernie W · 07-02-2008, 12:41 PM

I have a Craftsman riding lawn tractor w/17-1/2 HP B/S engine. When running at full throttle with the mower blade engaged, it runs fine. But when I disengage the blade and keep the throttle open, the mower snorts, farts, misses and ultimately dies. After that, it starts right up and does the same until I engage the blade.

A friend told me that the problem lies in the low speed idle throat and that the carb needs to be cleaned. I've cleaned it 5 times already with no improvement.

My issue though, is that this motor has an idle mixture screw that has a limiter cap on it. In effect, it prevents the operator from setting the idle mixture way too rich or way too lean. The limiter cap is not removable. The manual states: "This engine is equipped with an idle fuel adjusting needle with a limiter cap, which allows some adjustment within the limits allowed by the cap. Do not attempt to remove the limiter cap as it cannot be removed without breaking the asdjusting needle."

I believe my stalling problems lie in here because I've cleaned everythuing else so many times. So, how do I get the adjusting needle out to clean this fuel passageway too?

Thnx.

07-02-2008, 12:41 PM	#1 (permalink)
Bernie W Registered User Join Date: Jul 2008 Posts: 6 OS: VISTA	Low Speed Roughness I have a Craftsman riding lawn tractor w/17-1/2 HP B/S engine. When running at full throttle with the mower blade engaged, it runs fine. But when I disengage the blade and keep the throttle open, the mower snorts, farts, misses and ultimately dies. After that, it starts right up and does the same until I engage the blade. A friend told me that the problem lies in the low speed idle throat and that the carb needs to be cleaned. I've cleaned it 5 times already with no improvement. My issue though, is that this motor has an idle mixture screw that has a limiter cap on it. In effect, it prevents the operator from setting the idle mixture way too rich or way too lean. The limiter cap is not removable. The manual states: "This engine is equipped with an idle fuel adjusting needle with a limiter cap, which allows some adjustment within the limits allowed by the cap. Do not attempt to remove the limiter cap as it cannot be removed without breaking the asdjusting needle." I believe my stalling problems lie in here because I've cleaned everythuing else so many times. So, how do I get the adjusting needle out to clean this fuel passageway too? Thnx.