WOT and Prop Pitch?

[G.H Cook]

I have a 1991 larson 170 all-american. 1800 dry weight, 190hp 4.3l mercruiser, aluminum prop 19p. WOT currently 5500rpm at 46mph. My question is should i be running a 22 or 23pitch prop to bring my rpm down to 4400-4800 WOT? I would like to gain top end mph not in need of holeshot. I would like to get use out of all my hp and not over rev.

thanks for any info

 

[Robbabob]

Re: WOT and Prop Pitch?

Hi and welcome aboard!

You are thinking in the right direction. Make sure your current prop is not damaged; bent or damaged edges can increase rpm a lot. Making a radical pitch adjustment could really hamper your performance.

See if you can borrow 21 in great condition to see how it performs.

 

[QC]

Re: WOT and Prop Pitch?

You might even be able to get to a 23 with a 3 blade (stainless). Your numbers appear right. If they are, I think you have a significant speed opportunity; maybe 50 which would be a huge jump.

 

[180shabah]

Re: WOT and Prop Pitch?

You are definitely thinking in the right direction.

Watch that throttle hand until you get the prop swapped - you are flirting with vlave float...she'll bite ya' when your not expecting it....

 

[G.H Cook]

Re: WOT and Prop Pitch?

Yes, thats what i was thinking 180shabah. Also hoping a fully loaded boat will help keep the rpms down until i can get a new prop.

thanks for the help

 

[QC]

Re: WOT and Prop Pitch?

Also hoping a fully loaded boat will help keep the rpms down

Reminds me of a George Carlin bit, "These are words that have never been said together before" . . . lol

 

[Robbabob]

Re: WOT and Prop Pitch?

yeah

:facepalm: