I have a Mercruiser 140 that I have rebuilt because of a leaking 2 piece rear main seal and low compression (115-120psi). It had a rough idle, and was burning oil.
The serial # is 2675390. (Serial Range Mercruiser 120/140 1967-1969 2062141 THRU 2791956).
What I did:
Honed the cylinders. (all...