I need help picking a new prop!!

[whit71]

I recently bought a 2000 Four Winns 180 horizon with 4.3 GL Volvo SX (1.79 gear ratio) it has alum. Volvo prop 14 1/4 x 21 that looks like it was run aground there is about a 1/2" mising off of each blade. Boat is running 41 mph (GPS) at 4800 rpm Volvo recommends 4200-4600 on the GL 2bbl carb. Im looking for more pull out of the hole and more stability on plane the boat rides ok but if you trim up a hair to much it porposes like crazy I put a hydrofoil to get more lift it helped but I still want more stability. I know i want a 4 blade SS been loking at the Stiletto Bay Pro II I think I want the 22 pitch to lower the top end rpm, but Im worried i'll lose bottom end. This may sound crazy but could the 4800 rpm be from the 1/2" of prop missing from the blades? I just can't afford to buy the wrong prop to much money to throw away, and the boat is from out of town there is know Volvo dealer in the area to try a loaner prop. Any help would be appreciated. THANKS

 

[usskydvr]

Re: I need help picking a new prop!!

If the 'cut-off' looks machined it could be the prop design. Some props (Michigan Ballistic) blade ends are flat. check out the Michiganwheel website for their prop catalog. It has lots of very useful information. also the Mercury
prop selector tool http://www.mercurymarine.com/propellers/prop-selector/#

 

[whit71]

Re: I need help picking a new prop!!

If the 'cut-off' looks machined it could be the prop design. Some props (Michigan Ballistic) blade ends are flat. check out the Michiganwheel website for their prop catalog. It has lots of very useful information. also the Mercury
prop selector tool http://www.mercurymarine.com/propellers/prop-selector/#

It is definetly not machined its was very ragged i tried to smooth it with a file just to get rid of the rolled metal along the edge.. Ive tried the mercury site problem is it only goes to 2001 year and in the volvo sx thats a 1.66 gear ratio it tells me my numbers are wrong.. Thanks for taking the time reply..

 

[steelespike]

Re: I need help picking a new prop!!

You should be able to have the prop repaired and get some new performance numbers.Most likely your high rpm is caused by the prop.I feel your boat should approach 50.If you select a prop based on your present numbers your fixing a problem that may not really exist.A Solas Amita4 will give you excellent low to midrange performance for 1/3 of a ss prop.

 

[whit71]

Re: I need help picking a new prop!!

I will think about the alum. vs. SS but I dont really want to spend money to fix the prop i have. What is your opinion on the pitch should i stay with a 21? not sure why but most of what ive read says to drop 1" of pitch if you go to a 4 blade from a 3, is this because of more mass/weight of the extra blade? Any input will be greatly appreciated!!

 

[steelespike]

Re: I need help picking a new prop!!

The extra blade adds drag.I've seen plenty that went same pitch to same pitch
with excellent results. I would be inclined to go to a 20,if you can find one.
I feel its better to be on the light side you can allways throttle back slightly
if it over revs if you end up over propped its not good to run over propped.
Based on your present prop I would say you will see a vast overall improvement.

 

[whit71]

Re: I need help picking a new prop!!

Thanks for all of your help ordered the Bay Pro II 20" I'll let you know how it turns out in a couple of weeks. Have a happy and safe 4th!!