[quote=&quot;John Schwiebert&quot;:3vnntxg8]Before you pull that engine do 2 things. See if you lost a screw from either the choke or throttle shaft in the carburetor. Have seen that more than once and if they land on top of the piston they will knock. Have you done any troubleshooting to see which cylinder has the problem[/quote:3vnntxg8]

John good thought. The knock does seem to be coming from top of engine, oil pressure is still at 45-50 psi. If its a screw embedded in piston top, maybe just maybe i can get it off thru plug hole. Its a sharp knock, not a dull thud like a rod bearing. Will look there first tomorrow, and go from there.
Oh tach hours are 6187.4
John carb/fuel issue i resolved. There was debri in top of gascolator stem going into tank. removed fuel line to check fuel flow was just a dribble, enough for low power, but plowing/discing it starved for fuel. Wondered why they put an electric fuel pump on tractor, does anyone know where to get a engine driven fuel pump rebuild kit for this tractor? rather have it hooked up then electric pump. But would still like pages for checking power valve on this carb john and others for fine tuning the carb.