Factory prop pitch??

[ScottinAZ]

Trying to figure out if I have the factory pitch prop on my 1975 Evinrude 50 engine. Its marked as a 12 1/4 x 15. I bought the boat used, and is in the middle of a refit (yeah, I know). I figure that the factory prop should be a good starting point for tuning and all. The engine is attached to a 1976 Invader Capri 15' trihull. Stated WOT for the motor is between 4500-5500 rpm (IIRC, could be 5500-6500, would have to check). This boat hasnt seen water (except in the foam) since at least 1998, so I dont know if there are any issues with the prop that I have, except that its a bit ragged looking.

 

[steelespike]

Re: Factory prop pitch??

If the prop was with the boat check the size on the barrel or under the prop nut.75 brochure indicates 12 1/4 X 15.But that doesn't mean much as the prop would have been selected to fit the boat.

 

[ScottinAZ]

Re: Factory prop pitch??

12 1/4 x 15 is what I have, There are no reccomendations from the boat mfg, so I will start with the engine factory pitch prop, hey, gotta start somewhere....... Thanks

 

[junior1113]

Re: Factory prop pitch??

need to be within recomended wot rpm range to get best performance and engine life. that motor on a john boat would need like a 19 pitch and if it were on a heavy 17' boat it would need like a 13 pitch. if u dont have a tach i would rec. buying a mini tach. good luck

 

[ScottinAZ]

Re: Factory prop pitch??

Since I dont have the boat in the water yet, I dont know what its performance issues are. Being as the prop that I have now is about 90% shot, I need to get a new one anyways. I have a tach on order, will have to see what happens with it once it arrives, and the boat is seaworthy