supermajor running away

[vtjoe]

this has happened to me before-- while idling, holding up a log with the hoe and cutting firewood chunks, the motor will just start revving up - to max rpm if i don"t move fast enough!! I pull the fuel shut off and restart the motor and everything is good for a while.... then same thing again. It has a Simms Minimec pump with no vacuum governor... so is there a mechanical governor that I need to service and how???? do I need to change the oil? How does it all of a sudden get extra fuel to run so fast? Any help is appreciated.
 

[ShadetreeRet]

I'm no expert on fuel injection, but I wonder if it could be sucking air somewhere? On many engines excess air will cause one to rev up as well. Interesting problem, good luck.
 

[Bendee]

Like ShadetreeRet, look for excess air intake first, find it the cheaper option.
Clean out the oilbath and fill to oil level.check hoses for cracks etc.
 

[Bendee]

Minimec..How long since you put oil in the pump?
There are two plugs on the lower half. the bottom one is the drain, one immediately above is the oil level.
Drain the system and replace the plug. remove the one above.
On the top rearward of the injector pipes is the filler plug. put oil in there until it comes out the bottom hole.replace plug and see what that does.
 

[vtjoe]

here is the latest- I did what was suggested, the air cleaner was fine-- the oil that drained from the pump was a little thin and looks somewhat rusty in color. so new was good. I put in straight 30W and am planning on changing it again soon. I also found an exploded diagram of the pump. very difficult to find as mine has no built in fuel pump or ANY hoses or vacuum governor. just the tach drive sticking out the back and inside throttle lever connection next to the block. diagram shows a rotating centrifugal governor looks like i need to investigate further