trouble with my variable speed control

[Brad in Wisconsin]

I have a M610 sn 202415 with V-4 Wisconsin gas engine. I have replaced the variable speed cylinder o-rings and the variable speed valve o-rings with the result being that the variable speed works EXCEPT when I speed it up with the valve, as soon as I let go of valve ,is starts to slow down...where is the oil leaking thru? do I have a speed check valve? I dunno do you? Thanks

 

[6brnorma]

There are several possibilities…….There are a total of 4 O-rings and one seal inside the sheave. Typically if there is a fine mist of fluid when you activate the valve the leak is in the root-swivel assembly seal (pt #6516301) and O-ring (pt #25K-20005) or gland O-rings (2…one inside and one outside) or the one O-ring on the shaft itself. My experience is that 90% of the time when the sheave bleeds back it is one of these. Very rarely do I have troubles with the valve but since you replaced O-rings it is certainly a possibility. It is very easy to damage these O-rings when reassembling.