I have a 1996 Mercury 4 cylinder 40hp with 125 Psi across all 4 cylinders. I also have a mid 80s Mariner/ Yamaha 40hp 2 cylinder with 123 Psi both cylinders. I'm not sure what factory specs are, but maybe this would help.
125 is the least
I should be equal on all cylenders and about 110 to 120
The dry weight for a 1997 model, 40 hp Mercury outboard, is listed at 177 lbs.
The dry weight of a 1985 model, 40 hp Mercury outboard is 152 lbs.
A 40 hp Mercury outboard, serial number 7032376, would be a 1974 year model.
A 40 hp Mercury outboard, serial number 6052990, would be a 1982 year model.
An 40 hp Mercury outboard, serial number 7197998 would be a 1983 year model.
A 1990 Model, 40 hp Mercury outboard, has a dry weight of 182 lbs.
I have a 2005 and compression should be close to 120 psi. Normally a good engine will have compression between 115 and 130 psi but a leak down test should be performed also to know the full condition of a cylinder.
100 psi to 140 psi.
yes
50:1