i just got it and took it to the mechanic to get it checked out and 3 of the cylinders have 115 psi and the 4th has 90 wondering if it is going to hirt the moder to just run it or should i rebuild
That is a 25psi differential well past the acceptable 10% variation . There are several reasons for this, A scored cylinder wall or piston, Bad reed valves on the low reading cylinder, or as simple as a stuck piston ring from sitting up too long without being run. In any case
running this engine under load may trash the whole powerhead.
