What Type of Oil

[Hal Davis]

My 14 year old son just purchased a 7.5 HP Corsair outboard made in 1949, we think. It says to mix 1/2 pint of SAE 30 to one gallon of gasoline. Is this still good advice or should we use a modern two cycle oil?

Also, do these have a plastic/rubber impeller that we need to check out before we try to run it? If so, where would it be located?

Thanks,

Hal Davis

[George Andreasen]

Use any modern two stroke oil mixed in the ratio given by the engine plate as the new oils are far superior to ordinary motor oil. Walmart has a one gallon "house brand" that I believe is called Master Tech and costs about eight dollars.
My old outboard service manual says that Corsairs were built by Scott Atwater and parts are now handled by McCulloch. It also states that the cooling system has a rubber impeller located in the lower unit. The illustration shows a common star shaped impeller which is still available. I found one for my Mercury on Ebay and I know they're on the internet.
Do an internet search for "antique outboards"...you'l find a whole crew out there just like the stationary engine groups. All will be eager to help. Have fun!

[Hal Davis]

Thanks, George.

[Doug Hudgel]

Go to the AOMCI web site, and contact Don Dwiggins at 479-641-2413 for manuals for your motor, very reasonable.

[Andrew Mackey]

As old as your engine is, it may have plain bronze bearings. If that is the case, and the engine is calling for a more oil rich mixture (8 or 12 to one), the modern oils will not provide suffecient lubrication to the bearing surfaces. Even for those calling for 16 to one, the new lubricants - note I did not say OIL, do not provide enough lubrication to plain bearinged, low speed engines. Check your specs, if you have them. Some older engines alsorequire SAE 40 or higher NON Detergent oil, for the mix. The new lubes do not have the viscosity required.
Andrew