Just bought a non-running 425 Magnum 6x6. Guy said previous owner had motor rebuilt (3 years ago or so.) Electric start began failing and he put a new recoil on it which he broke immediately.

I get it home and put a new recoil on it and the pull is incredibly hard....so much so that I think I'm going to break the new recoil assembly. I also installed a new starter which won't roll it over either.

I'm thinking maybe a hydro-locked situation so I pull the plug and the motor rolls over fine with both pull start and electric start. The cylinder was dry however.

Checked the valve lash and it was right on at .0006".

Checked the compression relief spring on the end of the cam and the spring was strong and keeps the metal piece against the dowel like it should. Was able to get the motor to turn over a few times with compression tester installed....the result was 145 lbs.

I have a small camera that I dropped into the cylinder. Couldn't get a pic of the entire chamber because of the angled engine but there are marks on the center piston and a couple of grooves once side of the piston top. I will include the photo.

Anyway....I'm at a total loss at this point. Not sure how to proceed and diagnose. Would sure appreciate anyone's help who might know what the heck is going on! Sure could use some advise.