hdb wrote:
I have recenlty purchased a olde double hull fiberglass speedboat with
a 1972 johnson 50, I beleive the prop that it came with is incorrect.
It was a 14" by 17 pitch all the literature suggests that is a wrong
prop but I can not find any guess on what size prop should be used. Any
help wouold be nice. Thanks
Wes


That's a "large gearcase" motor... and it is in fact 14" diameter. You
are rated at 50 HP @ 5500 rpm, the pitch should be 15" (which is
actually 13 3/4" diameter from the factory) for that application, which
should land you within the 5000-6000 rpm operating range for that motor.

OMC #391198

or

Michigan #011002

You should see 30-33 mph with that combo.

Rob