Chainsaw Repair

Whats the compression supposed to be on this 3700 when using a compression tester?

I would say anywhere from 140 psi to 170 psi.    The 3700 with the 2 thin rings always seem to run a lot higher compression than the 3800 which seem to be around 125 psi to 150 psi.

Yep it is time to pull the cylinder and see how bad the damage is.   You never know it could just be carbon and some stuck rings.

Yep, I guess well know what model this really is now after I pull the cylinder off.  Hope I can get enough of the cylinder gasket to make one with the 1/16 gasket material. Poulan discontinued the gasket.

The chainsawr parts site has used cylinder that had good compression 1 13/16 dia for $75.

Do not bother with the cylinder base gasket.  These saws have enough squish that you can loose the gasket and still take another .020 thousands off the base.   I have used yamabond on a lot of these with no problems.

Also make sure the cylinder for a 3700 has a piston for a 3700.   The 3800 will not mix with a 3700.

Is there diameter size for the pistons that tells the 3700 and 3800. Here's the part number for 3700 piston 530010355 and cylinder is 530024799

The 3700 has two thin rings and the cylinder is chrome and the piston is aluminum.
The 3800 has two thick rings and the cylinder is aluminum and the piston is chrome.

You cannot not mix them.

I agree the cylinder and piston does not look to bad.   I think I would clean the cylinder up and the piston and put some new rings on it with out a base gasket and see how it does.