I have an stx 38 with a black deck and 13 H.P. engine. The issue I am having is after I start it. It starts great, but when It goes above half throttle, it starts to race like the engine wants to blow. I can move the throttle down and it will run like a new mower lower down. I can't figure it out. Someone said the butterfly valve and someone else said something else. Anyone have any ideas? Anything would be appreciated..Thanks!
STX 38 running trouble
- Thread starter rosey65
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xp14629
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Good possabiltly of both options. I have seen the throttle butterfly in the carve (the one closest to the engine) come off the shaft and get lodged. Normally when this happens, the lever has no response. The linkage binding between the throttle shaft and the governor arm could cause this. If these both look good, you could be fighting a governor weight issue inside the engine.
xp14629
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The internal governor involves pulling the engine and disassembling the crank case. Then reassembling and setting the backlash on the gears. Not bad if you have the time and are experienced in the internal workings of a small engine.