I just bought a 45MB, fairly original.
Engine compression is 1-90, 2-80, 3-60, 4-90#.
I'm hoping it is just carbon on the valves and will try cleaning with SeaFoam first.
I could not even find the # of Quarts it takes to change the oil?

I'm and amateur and any suggestions about trouble shooting low compression is welcome. Also, how many dern quarts does this motor take?!