prop and gear ratio

[RLT III]

so i switched Lu's and i went from a 1.81 i believe (from marking and counting drive shaft rotation) to 1.64 so I'm not sure where i will be my prop is 10 3/8 x 13

will i need another now or will i be close enough

look to signature for boat motor

 

[Bondo]

Re: prop and gear ratio

Ayuh,... Run it to see where the rpms at WOT are, then reprop accordingly...

 

[hwsiii]

Re: prop and gear ratio

RLT, if you were at 1:81 to 1 and then went to 1:64 to 1 gear ratio, and your motor was turning 5,500 RPM with the 13" pitch now it will lose right at 500 RPM to 5,000 RPM, but your WOT speed should stay the same.



H

 

[RLT III]

Re: prop and gear ratio

Thanks thats ok right

 

[RLT III]

Re: prop and gear ratio

so I ran it this weekend and it looked like my rpm was 4800-4900 and that's to low so do i need to go up to 15 or down to 11

 

[hwsiii]

Re: prop and gear ratio

RLT, you need to go down to an 11" pith in the same prop you have now.



H

 

[RLT III]

Re: prop and gear ratio

Thanks for the help looking for one now

 

[hwsiii]

Re: prop and gear ratio

You are very welcome.



H

 

[RLT III]

Re: prop and gear ratio

okay so same diameter dropping to 11 which one you do you suggest of these
well as you know I have a 13 3/8 and only Michigan offers that in 11

But others offer 10 7/8 11 what do you think I'm about to buy
from here of course

 

[hwsiii]

Re: prop and gear ratio

I assume you mean 10 3/8" Diameter, and if you will tell me your WOT RPM and speed I can help you find a better prop.



H

 

[RLT III]

Re: prop and gear ratio

yes diameter, With the old LU i was around 5500 don't have the speed but i would say around 35

With this LU 48-4900 and maybe...30 probably less

the motor should be 53-5800 and at least hitting 37mph the boat weighs around 700 and we'll say 1150 loaded gear and 3 people

that's the best I can give you don't have gps

 

[hwsiii]

Re: prop and gear ratio

You might try reading this for a better understanding of changing props for better performance, and for the major differences between aluminum props and stainless steel.

http://forums.iboats.com/showthread.php?t=369057


If you will take the boat out and get me an exact WOT RPM and GPS speed I can then tell you which prop you need to buy.



H