1967 20hp johnson and 1972 25 hp evinrude prop

[fishermanof93]

I have been buying and fixing up a couple of outboards to try and sell both have spun hubs. I don't plan on testing and finding the exact prop from rpm range was just wandering what experience if any you guys have had with the prop pitch on these on a 14 to16ft flat bottom well loaded. I am really looking for top speed out of these but plan on selling one of them so really just need the best one for the motor they offer a 7 9 10 & 11 pitch props and the 11 is a 9 1/4in dia prop instead of just a 9 in. what do you guys suggest.

 

[Sea Rider]

On portable engines, usually a medium pitched prop is delivered with engine, on light to medium applications works quite well near its max wot rpm factory stated. From there you can maximize prop to suit best your current boat/load needs. To specify best prop pitches for both engines will be shooting in the air blindly as there's no previous data on how well factory delivered props were performing, as going from there.

If well loaded a less pitch prop would be advisable to shoot revs a bit, which one ? who knows..

Happy Boating

 

[steelespike]

I think you should pin the spun hubs and and do some testing.
We don't know the motors final condition They both may end up a little tired.
Based on your information I would say eliminate the 7 and 11.Put the 9 and 10 in a barrel and pull one out.

 

[fishermanof93]

the motors are actually pretty exceptional compression tested 134 on both in the 67 and 128 top 126 bottom on the 72. all gears and seals are good on both and both magnetos rebuilt and have excessive spark the 67 starts and runs like a dream but haven't started the 72 yet. but I think I am going to put the 10" pitch on both.