Factory Compression specs for 50's outboards

[jbjennings]

Guys,
I've noticed a lot of questions regarding compression readings on old outboards and have done just a wee bit of research for my own knowledge and can't find any factory specs.
Does anyone know the original factory compression for 50's OMC engines, say from 3 to 25hp, from 1953 to 1958? I would really like to know what kind of compression these had when NEW since I was out exploring the universe when they were built. If anyone knows a website to look for them I'd appreciate it.
Thanks,
JBJennings

 

[tashasdaddy]

Re: Factory Compression specs for 50's outboards

as far as i know they have never published the compression reading on any of their motors.

 

[JB]

Re: Factory Compression specs for 50's outboards

What Daddy said.

This is because guages and technique vary too much to set a psi number as a standard. The important thing is that the cylinders read within 15% of each other. I never saw an outboard that had more than one cylinder go bad at the same time.

 

[jbjennings]

Re: Factory Compression specs for 50's outboards

Thanks guys,
THat is weird, though! I've seen compression specs for motorcycles and cars if I remember correctly, but not outboards. Seems like they would publish the correct specs and if your gauge is not accurate, tough luck. At least you would have a ballpark idea of what it should be. I have a cheapo O'Reilly's comp. gauge and although I've already had one stop holding the pressure, they've both been pretty accurate as far as I can tell. They give me the same basic numbers on my oldies that others have. My 10 horses, for example, that run good all have about 85 lbs. which seems to be about what everybody else has, except Chinewalker, who has one practically "new" that has more.
Thanks again,
JBJ

 

[wbeaton]

Re: Factory Compression specs for 50's outboards

I have yet to see a 1950's OMC 10 hp with anything, but 80 something psi. Even my nearly new 1958 is only +80 psi.