Need Help on a Stihl 038 AV

lone wolf · Mar 11, 2012

That piston is worn out in the pic.Replace it .If you check the piston to wall clearance it will confirm this.

Stihlmech · Mar 11, 2012

The piston is not worn out. Machine marks on the sides and the top confirm that. What also I did see....the hole in the top of the piston. If it is not a hole the like I said before. Replace rings.

lone wolf · Mar 11, 2012

Stihlmech said:
The piston is not worn out. Machine marks on the sides and the top confirm that. What also I did see....the hole in the top of the piston. If it is not a hole the like I said before. Replace rings.

It looks like wear at the lower skirt hard to tell by the pic though!What about measure it.

jwillett · Mar 11, 2012

I took the rings off and put the piston in the cylinder, it was a really good smooth fit, my feeler gages are at work dangit. I may take it to work and measure everything tomorrow to see where I am at. I may throw a set of rings at it (per stihlmech) and see what happens as this saw is easy to work on, unlike the 025 I have been messing with.

Jim

jwillett · Mar 25, 2012

Well I put a new Episan piston kit in it and she started up on the third pull. At first it was blowing fuel back out of the carb really bad and would not idle. I pulled the carb and opened it up but did not find anything and put it back together. After that it started and ran great and would restare right up. I ran it for a little while but because I don't have a chain for it I shut it down. I want to break in in under a load. I enjoyed working on this saw, much more so than the 025 I have tore down and waithing on parts. I did buy a new compression tester from Northwoods Saw and checked the 038 just before I started it up and had 125 PSI, was hoping for more, maybe after it breaks in the rings it will go up.

Thanks to everyone for their help on this project.
Jim

lone wolf · Mar 25, 2012

jwillett said:
Well I put a new Episan piston kit in it and she started up on the third pull. At first it was blowing fuel back out of the carb really bad and would not idle. I pulled the carb and opened it up but did not find anything and put it back together. After that it started and ran great and would restare right up. I ran it for a little while but because I don't have a chain for it I shut it down. I want to break in in under a load. I enjoyed working on this saw, much more so than the 025 I have tore down and waithing on parts. I did buy a new compression tester from Northwoods Saw and checked the 038 just before I started it up and had 125 PSI, was hoping for more, maybe after it breaks in the rings it will go up.

Thanks to everyone for their help on this project.
Jim

It may go up 10 - 15 more but that will work fair at 125 for now .