Chainsaw Repair

Thought we better save more info by Tim aka fossil before it get buried again and takes forever to dig through to find other places.

fossil =  I suspect some of you may have Poulan Micro's with the oiler check valve which is located behind the clutch. They give up after some period of time as they have a duckbill check valve which dissolves and won't oil.

This will let you know how to renew the valve which is becoming difficult to find.

There is a duckbill and a brass bushing inside. I searched some time ago and someone had repaired them successfully.

The one I took apart looks like this. The screen is missing.

The duckbill goes in flange up followed by the bushing which is stopped by a shoulder in the body and then the screen which is MIA

I cleaned and reassembled the valve parts in the order in the above pic. The duckbill is Poulan PN 530026119 which is readily available.

As mentioned previously, I had filed the top off that valve to remove the screen so I had no room to put the screen back in. I'm not sure how much debris the screen keeps out as the three I have removed had clean screens. I guess I will see if I use the saw for some length of time.

A few notes.

When the bushing, which is a slight press fit goes in, make sure it is firmly seated against the duckbill. If it is not, air will leak back to the crankcase and no pressure will build in the oil tank.

I peened the bushing / valve body to keep the bushing in place.
If I do another I'll pop the rolled lip back with a shaped drift so I can put the screen back in.
Some other member(s) mentioned that they used some JB Weld to put the screen back on but I was a little reluctant as I wouldn't want it to fall off and end up in a bearing.

If you haven't run one of these before make sure you release the pressure in the oil tank by unscrewing the cap or it will keep oiling until the tank pressure bleeds off.

It works great.

That is indeed good info to save.

I might have put it in a thread here already too. I just cant remember anymore.   

I wish I'd known this a few weeks sooner. I threw away the bad check valve when I replaced it, not knowing it could be repaired.
Great write up, Thanks

The only thing that could be a real pain is trying to roll back the peen that holds the screen. I remember looking at that area and I can't envision how that could be possible. I'd like to hear/see how it's accomplished the first time. Someone here has to have an old bad one laying around. Give it a go.

Well I just tried dis-assembling one like the above instructions and it's a lot harder then it appears.

#1- trying to roll back the lip that holds the screen is very touchy. When I tried to pry the roll over up, it would break off. I got most of it up a little but like I said it'll break off if you try to go too much w/it. After breaking off about 1/3 of it during the process, the screen was loose enough to get out. I have to believe the rest will break when I try to crimp it again.  We'll see.

#2- the so called brass bushing was not in mine. If there is a bushing, I don't know how to get it out. It has to be a very tight press fit. I might have an earlier version that don't have the brass.  Mine looks like all the same material. I can feel a small ridge under it but I gave up trying to remove it for fear of destroying the valve. I even tried the drywall screw method, no dice.

I have a couple duckbills ordered, so when they come in we'll see where this takes me.