Outboard BarrelTest

[mercuryman]

Can a small motor like a Merc KE4 get to full power in a 55 gal barrel. I have a Tiny Tach and I get about 3600 RPM.

[frankr]

Nah, it was designed to run on a boat on the lake, not in a barrel. The boat moves away from the prop thrust, a barrel can’t go anywhere. I’m surprised it runs at a steady enough RPM to get a tach reading.

[creekrunner]

That’s what test wheels are for………..or you can cut down a suitable stock prop that needed repair anyhow………

[wiscoboater]

Creekrunner, Do you have any pictures or tips on cutting down a stock prop? I would like to see how this is done to make my own for testing.
Thanks,
Jeff

[garry-in-michigan]

It is usually done on a lathe to evenly reduce the diameter. This ignores the fact that water flow reduces the pressure and temperature of the exhaust, but is usually OK for short runs. Remember the horse power produced is absorbed by the water and shows up as increased tempriture. Also on long run times the exhaust has a tendency to aureate the water. This mix can reduce its cooling efficiency in the outboard. Many reasons why a larger water capacity is desirable. It almost goes without saying that a fan should be used to keep the exhaust away from the carburetor air intake.

Note third paragraph – this test was done in 1952 . . . 😉

[mercuryman]

I guess that answers my question a small engine won’t reach full power in a barrel. If I tried that with my Super Ten Merc it would through out all the water. Very interesting report Gerry.

[wiscoboater]

Thats a really interesting read Gary. Thank you for posting that.

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