can cup be added to aluminum prop???

[glastron50gl]

If have been trying to fine tune the prop on my crowne 270 w/ suzuki 140 4 stroke. I had a solas 4 blade prop 13.8 dia/15 pitch and it would not get above 5500 rpm with 27 gallons of gas and me. So I stepped down to the 4 blade 13.3dia /13 pitch prop and the rpms are 6400 where the rev limiter kicks in. Can pitch or cup be added to the aluminum prop? Thanks Nutinbitin

 

[Doernuth]

Re: can cup be added to aluminum prop???

Cup yes, Pitch no. Take to a REPUTABLE prop shop and they will hook you up for a reasonable fee of course.

 

[steelespike]

Re: can cup be added to aluminum prop???

Did you stick with the same brand with the 13. While diameter dsoesn't enter directly into the equation usually as pitch goes down diameter goes up.
A 900 rpm difference across the same brand is highly unlikely.
The solas amita to this point has been very predictable.
To the best of my knowledge you can repitch al. props as well as add or remove some cup.I would see if you can have them free up the 15.
You can also increase rpm and speed a little by raising the motor.
Usually the antivent plate just above the prop shoulds be about 1 inch above the bottom and visable at speed.The Solas 4 blade usually allows maximum height.
In the extreme you could gain 2 to 3 mph and some rpm.

 

[glastron50gl]

Re: can cup be added to aluminum prop???

I did use the same brand Solas 4 blade prop. They dropped the dia to 13.3 on the 13 pitch prop. Know what you are saying it does not make sense. How do they reduce the 15 pitch prop? And would that cause more slip? I have close to 305 slip now. Thanks Nutinbitin

 

[steelespike]

Re: can cup be added to aluminum prop???

I don't find a Crowne only Crownline and they are I/Os weighing 5,500 to about 7,000lbs. tell us about your boat. If yours is anything close to that its very heavy and underpowered. And would account for high slip numbers.What was the speed with the 15 and 13. I think they can reduce pitch up to 2 inches and can add or remove cup actual type of cup would depend on the boat.I would think you would need stern lift.