Difference a Stainless prop makes on my boat.

b.gagnon

b.gagnon

Master Chief Petty Officer
Joined
Apr 28, 2001
Messages
835
70hp Chrysler 1979 on a 78 sea nymph 165 f/s turning a 17p prop (cupped)<br />Good:<br />Gained 1mph <br />Can now make a very tight turn without sucking air<br />General turning was very smooth and much more stable<br />Smoother acceleration at all speeds<br />Overall handling was great. It was like driving a different boat!<br />Bad:<br />Lost 400rpm!!!!!!!!!!!!!!!!!(Oh no) I now only turn 4600rpm<br />I know that you loose some rpm’s when switching from aluminum to a stainless but this seems extreme……
 
LubeDude

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
Re: Difference a Stainless prop makes on my boat.

You can raise the engine now with that prop, where is the ventilation plate now in relation to the bottom of the boat?<br /><br />I wouldnt run that prop the way it is now, Its way too low on the RPM, its lugging your engine big time which isnt good. It can cause predetination and a burned piston.
 
b.gagnon

b.gagnon

Master Chief Petty Officer
Joined
Apr 28, 2001
Messages
835
Re: Difference a Stainless prop makes on my boat.

The plate is about even with the bottom of the boat, but to get it any higher I would have to drill new holes. The motor does not have power trim so I plan to get one over the winter. I think they have a five inch set back so I may be able to use it as a jack plate. How many rpm's can I gain by raising the motor???? max WOT rpm on this motor is 5100rpm.
 
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stevens

Senior Chief Petty Officer
Joined
May 4, 2005
Messages
799
Re: Difference a Stainless prop makes on my boat.

Too bad about the RPM-drop.<br />I think you now have three options.<br />In sequence:<br />try to raise the engine some,<br />have a prop shop take out some cup or some pitch,<br />or find another prop and use this one as a spare...(after all, it was only $54)
 
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PuddleJumper

Petty Officer 1st Class
Joined
Jun 6, 2005
Messages
314
Re: Difference a Stainless prop makes on my boat.

Once you add PT&T you may gain some rpm when trimmed. Are you satisfied with the hole shot you have now? If you are I would wait to see effect of trim. If slow hole shot consider lower pitch or getting prop reworked.
 
b.gagnon

b.gagnon

Master Chief Petty Officer
Joined
Apr 28, 2001
Messages
835
Re: Difference a Stainless prop makes on my boat.

The way it is now it is trimed out on the highest trim hole and the hole shot is very good. What does it cost to get a prop reworked?
 
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Salmonseeker

Petty Officer 1st Class
Joined
Jun 11, 2005
Messages
298
Re: Difference a Stainless prop makes on my boat.

Removing cup is usually not a good thing. This will usually make a prop less efficient and it will lose its water holding capabilities.
 
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