Prop question

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Rwebber77

Petty Officer 3rd Class
Joined
Dec 31, 2009
Messages
77
I launched my new to me boat today and noticed the prop is really dinged up so I'll be replacing it sometime this week. The boat is a 1988 19' Sea Ray with a 4.3L merc and "Sea Ray" outdrive, which I am assuming is basically an Alpha I with a Sea Ray label?

The current prop is a 19 pitch, 14.5 diameter 3 blade aluminum. WOT I am only hitting 4200 rpms (4400 - 4800 is where I need to be) and 37mph.

I would like to stay with aluminum but don't know whether to go up in pitch or not. Also, would a 4 blade offer anything? My goal in this new prop is all around performance. Won't do a lot of tubing or skiiing, just cruising mainly.

I appreciate any help at all. I hear you prop guys really know your stuff :D
 
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TilliamWe

Banned
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Dec 21, 2004
Messages
6,579
Re: Prop question

Well, if your current prop is "really" dinged up, it might not be a good baseline. But let's say it is doing about right. You DEFINATELY do NOT want to increase the pitch. In fact, you want to lower the pitch.
 
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Rwebber77

Petty Officer 3rd Class
Joined
Dec 31, 2009
Messages
77
Re: Prop question

It is definitely bad. By dinged up I mean each blade is missing a few chunks and what is there is bent up. To get the baseline I need maybe I should get the same pitch new and exchange if I need to. Otherwise I would have a back-up.
 
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steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Prop question

You may be able to have the prop repaired then do a test if a prop change is in order it will serve well as a backup.Don't make any changes till we get the good base line.
A 4 blade should improve your hole shot and help you stay on plane with less power. you may lose a little top end.
 
oops!

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: Prop question

something doesn't sound right.
a 14p and having to prop down???

to get you into the range of rpm you want, you will have to drop 2ins of prop. that means a v6/alpha 19 footer running a 12p ??? :confused:

something is whacked

on the side of your searay drive it will say the gear ratio. should be 1.86 ish. you might want to check that.
also you might want to weigh your boat with everything out.
compare it to factory specs.

at 42-4800 rpm wot....you are really working that v6.

your top end of 37 is ok....but something is out of whack.
 
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TilliamWe

Banned
Joined
Dec 21, 2004
Messages
6,579
Re: Prop question

oops! said:
something doesn't sound right.
a 14p and having to prop down???

:confused:

.
Click to expand...

Oooppsss, you have committed and "oopps". He clearly states that the prop is a 19 pitch. You read his diameter measurement.
 
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Rwebber77

Petty Officer 3rd Class
Joined
Dec 31, 2009
Messages
77
Re: Prop question

Thank you for all your input thus far. Where would a guy go to get the prop repaired? There are no local marinas unless I travel an hour to the Twin Cities.
 
oops!

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: Prop question

really....try iboats.for a prop..great prices..mega fast service...a lot of the guys here are raving about them

steelespike said:
Present prop is a 19" A 14" sure would be whacked.
Click to expand...

TilliamWe said:
Oooppsss, you have committed and "oopps". He clearly states that the prop is a 19 pitch. You read his diameter measurement.
Click to expand...

lol.....thanks for watching my back.....dont know how i missed that.....except it was posted really early my time....before my first cup of coffiee...:D
 
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Rwebber77

Petty Officer 3rd Class
Joined
Dec 31, 2009
Messages
77
Re: Prop question

I really appreciate the info, I inquired at 2 different places about repair for my old prop and based on the condition both of them said between $65 - $75 so I am ordering a new one either tomorrow or Wednesday. Once I get a proper baseline and correct rpm reading with a good prop I will post the results.

Thanks again, you guys really are a plethora of information.
 
JaseBosto

JaseBosto

Petty Officer 1st Class
Joined
Mar 17, 2010
Messages
389
Re: Prop question

that really sucks that your closest marina is an hour away. I have 3 different marinas within a 15 minute drive tops...maybe 4 marinas...
 
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