Recently, I got a new, 2017, MS391, my second one.
After I got through the loose flywheel, and got it timed and tightened correctly, It screams pretty well. When the chain is sharp, it cuts well for about a minute, then chain stretch cuts in. This is a STIHL chain, not sure what type maybe a RS3, or a RSC. Some oil is sprayed by the bar, maybe not enough. I have cleaned the chain grooves, and oil holes in the bar. The studs look to be not sticking out, making an oil leak, so maybe its a weak pump or a clogged line. I'm cutting dry, hard maple. Right now, I'm grinding the chain to 25 degrees, which seemed to be the angle that was there.
The oil filter will not pull all the way out of the filler hole, So I have blasted it with brake cleaner. I may try to running some ATF through it to see if there are places that need to be cleaned out in the pump system since ATF is 5 weight I believe. Maybe my bar oil is too heavy, I may dilute it with a little ATF and see what that does.
I'm trying to not learn how to rebuild an oil pump. I also don't want to change in the oil pump from my other MS391 which is half apart at the moment. I want to do simple things first.
Thanks for reading all that. This forum is very helpful. I am enjoying reading and helping here when I can.
Any suggestions?
After I got through the loose flywheel, and got it timed and tightened correctly, It screams pretty well. When the chain is sharp, it cuts well for about a minute, then chain stretch cuts in. This is a STIHL chain, not sure what type maybe a RS3, or a RSC. Some oil is sprayed by the bar, maybe not enough. I have cleaned the chain grooves, and oil holes in the bar. The studs look to be not sticking out, making an oil leak, so maybe its a weak pump or a clogged line. I'm cutting dry, hard maple. Right now, I'm grinding the chain to 25 degrees, which seemed to be the angle that was there.
The oil filter will not pull all the way out of the filler hole, So I have blasted it with brake cleaner. I may try to running some ATF through it to see if there are places that need to be cleaned out in the pump system since ATF is 5 weight I believe. Maybe my bar oil is too heavy, I may dilute it with a little ATF and see what that does.
I'm trying to not learn how to rebuild an oil pump. I also don't want to change in the oil pump from my other MS391 which is half apart at the moment. I want to do simple things first.
Thanks for reading all that. This forum is very helpful. I am enjoying reading and helping here when I can.
Any suggestions?