New Prop

[PaulKim]

New 90HP ELPTO, was getting 6000 RPM's with the prop I had from my Force 85HP. Pitch is 19. Don't know the Diameter.<br /><br />Just purchased a New Black Max 12 3/4 X 21 to decrease RPMs to recommended 5000-5500 at WOT. Now am getting 5100 RPM (with boat fully loaded, gas, kicker, gear)<br /><br />Should I try to get as close to the 5500 RPMs?<br /><br />What should I do to get the best speed (Top End)?<br /><br />Thanks

 

[PaulKim]

Re: New Prop

Getting 40.8 mph (GPS) at 5100 RPMs

 

[LubeDude]

Re: New Prop

Maybe someone that has more expertise on these engines can tell us for sure, but I would think you should have a bigger diameter prop, 12 3/4 sure seems small to me?<br /><br />Are you happy with the performance now? Personally I would opt for a closer to 5500 if it were me, you will have a better hole shot, and be a ble to carry more people.

 

[Laddies]

Re: New Prop

If thats fully trimed your as close as you get with out going to a prop shop and getting some custom work done, they should be able to bend that Force prop for you and make it work OK--Bob

 

[cwilt]

Re: New Prop

hey paulkim, <br /><br />also have a 90 ELPTO. i have the same brand prop but running a 23 pitch prop on a 17 ft bass, i get exactly 5500 rpm with boat loaded. don't rember the Dia. my hole shot is not that great, but top end is around 48 mph.

 

[walleyehed]

Re: New Prop

PK, is your engine mounted directly on the transom at the lowest point???<br />If not, you should be able to lift the engine a hole and test...the R's should come up a little. If ventilation doesn't occure, lift another hole and test. You should be able to pick-up some speed by reducing Lower unit drag, which will increase R's as well.

 

[PaulKim]

Re: New Prop

Walleyehed, I believe that the OB is mounted correctly. It was too low and was kicking water into the motor well. The shop raise it up for me. The ventilation plate is slightly higher than the bottom of the transom. In addition I can't go up any higher without drilling new holes as I am using the bottom most holes on the mount. <br /><br />I would like to clarify, in regards to the Old Force Prop 19P - When I was getting 6000RPMs, the boat was not fully loaded up with kick, gear etc... <br /><br />What impact will moving to a 13 X 19P have?<br /><br />I'm thinking that it should increase the my RPMs and top end, but would like to confirm with you experts.<br /><br />Thanks