454 help needed

ljw · Apr 5, 2009

I bought a 454 gas utility that seamed to need a carb cleaning. It stumbles when I increase the throttle rapidly or when the governor is activated. I have installed a new carb kit, cleaned it thoroughly, several times, but no change in performance. I replaced the intake/exhaust manifold gasket, spark plugs, points, wires, checked the compression (150 on all), set the timing and even slightly advanced the timing and still no change in performance. It starts fine, runs well, has good power but still falls on it"s face when you throttle up quickly or when the governor kicks in. I don"t know where to go from here. Any suggestions?

JimB2 · Apr 5, 2009

Hi, my first disclaimer, I have never worked on gas model of 454 only Diesel model but the usual cause of the stumbling when throttle is advanced rapidly is to lean of gas/air mixture. One of the causes was vacuum leaks and since you have replaced the manifold gasket it s probably not a vacuum leak. Another was the low speed/idle jet being adjusted to lean. I looked at caseih.com parts for C-152 gas engine carb and did see an idle adjust screw for carb, so try openning idle adjust screw an 1/8 of a turn at a time and see if this helps any.

JimB

454 help needed

ljw

Member

JimB2

Well-known Member

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