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Riding mower ran too fast, now backfires and hard to start

#1

M

mapleguy

Kohler CV15S engine on my old Sears riding mower. Was running fine, then suddenly I noticed it was running really fast and power was missing. Shut it off and it backfired before re-starting, still was running full out. I checked the timing because of the backfire but the shear key is fine. Searching online it seems that the interior part for the governor is broken. After it cooled, I tried to start again to try to confirm the problem, but now it just backfires and I can't get it to run. Would this be typical of a broken governor or is there something else to check first before I open it up? Thanks.


#2

I

ILENGINE

The backfiring and lack of power could also be caused by a faulty hydraulic lifter. Lifter over pumped preventing valves from properly closing.


#3

M

mapleguy

Thanks ILENGINE, I didn't even know these engines had hydraulic lifters. If it is over pumped, will it bleed down after sitting for a while or do I need to replace it? Is there a relatively easy check to see if this is a problem, like removing the valve cover to check for valve opening and closing?


#4

I

ILENGINE

Normally they will bleed down, but on occasion they will fail and overpump causing it to hang the valve open. Issue can also happen with using too high a viscosity oil during cold weather. Have come across issues with people using 30w below 50F causing over pump


#5

Tiger Small Engine

Tiger Small Engine

mapleguy said:
Kohler CV15S engine on my old Sears riding mower. Was running fine, then suddenly I noticed it was running really fast and power was missing. Shut it off and it backfired before re-starting, still was running full out. I checked the timing because of the backfire but the shear key is fine. Searching online it seems that the interior part for the governor is broken. After it cooled, I tried to start again to try to confirm the problem, but now it just backfires and I can't get it to run. Would this be typical of a broken governor or is there something else to check first before I open it up? Thanks.
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Remove valve cover and visually check valves for any problems such as push rod bent, etc.

Start engine and hold the governor arm so it doesn’t over speed and see if governor is fighting back or not. I have to go in deep on my Vanguard 35 hp next week for a bad governor.


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