Small Engines (Lawn Mowers, etc.): Honda GC160 governor, throttle return spring, honda gc160

Question
I have a Honda GC160 5hp OHV engine. It only has about 15 hours on the engine which has been mounted on an old snapper tiller. I had to replace the intake valve after loaning it to a family member but that's another story. After replacing the valve and assembling the engine, it will start fine but immediately goes to full throttle even with the throttle control set to idle. I have checked all the linkage and springs from the governor to the carb. I have made the governor adjustment several times and I even split the case again to check the condition and operation of the governor weights and other parts inside the engine. Everything appears to be fine. With the throttle return spring disconnected, the governor arm and throttle valve move freely but when I connect the return spring, the throttle valve instantly goes to the full throttle position and never moves from there with the engine running or off and full throttle or slow. The service manual says with the throttle lever in the slow position, check to see whether the carburetor throttle valve is fully closed. Well it's not closed and never does but the manual doesn't say what to check or do if it isn't closed. Can anyone shed some light on what the problem is or what I might be overlooking. Sorry for the long post but I wanted to include as much detail about what I've checked and done as possible.

Answer
hi mike  


sounds like you have adjusted the governor  with throttle plate a full closed and  adjusted the governor shaft fully clockwise as you should as this places the slider and governor spool and cups in the correct postion to remove slack / wear from linkage system

what need to try is  loosen the governor shaft clamping nut and move the throttle plate and linkage to full open  ( do not use throttle control on engine to do this ) use your fingers
hold throttle plate on carb in  this position and turn the governor shaft clockwise fully ( do not force ) and tighten the clamping nut  

this leaves the throttle plate at full open ( while engine is stopped ) and has the governor spool and cups etc fully retracted and slack removed and places it in the correct position

i will assume all control and governor springs are ok and in position - with no binding  etc


cheers  paul  


give it a try   


keep me posted