I'll express my opinion that the compression readings you have gotten, will actually fall within the acceptable range............IF this engine utilizes a "compression release" mechanism (it's an automatic thing and requires no action from the operator). A "cylinder leak down" test will give a more accurate assessment of the "health" of the engine, but requires a "leak down tester" and a source of compressed air (also knowing how to set the piston(s) to the proper position and a way to "hold" the engine firmly in that position against the compressed air is a must). You should probably go ahead and ask for walt2002's in depth instructions for THE CORRECT PROCEDURE for valve adjustment. You can either ask for his e-mail here or search for it in some other posts, he has published it many times. If, after you know the valves are set correctly, you do another simple compression test, you should find that the readings between the 2 cylinders to be closer in value than they are now. You might also want to do a "wet test" following the dry test you have done thus far. A wet test is done by squirting about 2 tablespoons of clean motor oil into the cylinder, spin the engine a couple of turns and then hook up the compression gauge and take a new reading. IF PISTON RINGS are faulty, you will see a rise in compression of from 10 to 20 PSI. Oh.....a compression test must be done with the throttle wide open.

To the best of my knowledge, B&S does not publish compression specs. I would say 85 is probably OK, 62 is too low AND too much difference between cylinders. I would suspect a leaking head gasket on the low cylinder. This is common on this engine and especially when it has run hot with clogged cooling fins as you have described.

If it were me, I would replace both head gaskets and of course that will entail adjusting the valves.

Check out the air cleaner fit.

Actually, I should not have said any of this without knowing what ENGINE you have. You see, GT235 doesn't tell me a darned thing about what engine, really need the engine model number and I am not going to look it up.

Walt Conner

According to the B/Stratton sticker on the side of the engine, it is a YBSXS 5702VR. It is the Vanguard engine.

A cylinder leakdown test is the only way to reliably test a compression release equipped engine like this. However, the few times I've seen a compression test for one the two cylinders are supposed to be within 20psi of each other. A valve could be out of adjustment causing the difference you are seeing. Adding oil to the cylinder to check the rings is a good suggestion from the previous poster.