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View Full Version : MERCURY CLEAVER PROPS ON STV BOATS



GB
07-30-2001, 09:18 PM
I HAVE AN STV MOD VP WITH A 260 EFI WITH 32 CC HEADS AND OTHER SMALL MODS TO ENGINE. I RUN A 28 PITCH MERCURY CLEAVER FOR TOP END AND TO DATE 9200 RPM IS MY BEST. MY QUESTION IS WHAT IS THE DIFFERENCE BETWEEN A CLEAVER WITH LITTLE RAKE AND A CLEAVER WITH A LOT OF RAKE? MY SON RUNS AN ALLISON DRAG WITH A 260 EFI AND RUNS A 30 PITCH MERCURY CLEAVER WITH A LOT OF RAKE. HIS PROP ON MY BOAT GIVES A LOT OF STEERING TORQUE, MINE HAS VERY LITTLE TORQUE, SO HAVEN'T HAD HIS WIDE OPEN AS OF YET. ANYONE HAVE EXPERIENCE WITH BOTH STYLES OF THESE PROPS AND WHAT ARE YOUR THOUGHTS AS TO WHICH IS BEST?

AnthonySS
07-31-2001, 02:19 PM
Dear GB,

Most of us that have been running STV’s for some time will agree that a merc 14 ½” x 30” Cleaver is a choice/ favorite prop on an STV with and hi-perf merc. These props are low rake (+/- 18-22°). I have never seen a hi rake 30” Cleaver, by Mercury at least.

On the other hand, Mercs 32” Cleavers are hi rake (26-28°). I have never liked the use of hi rake wheels on my STV, They tend to provide too much bow lift and make the boat want to roll/lean to port with large torque compared to the low rake.

Your 28” Cleaver is certainly a low rake just by the way you say the steering load is light. I would stick with the low rake wheels on the STV, Try a 30” but not your son’s especially if you never have more than 2 people in the boat. What make is that 30” Hi-Rake.

Sincerely,

AnthonySS

Firestarter
07-31-2001, 02:30 PM
I too have never seen a high rake 30 from merc, but I do know that the mazco cleave has a lot more rake, and as such more torque.
Side note, In my experiance what works on an allison does not work on an STV.

RT

GB
07-31-2001, 03:42 PM
[THE PROP MY SON HAS SEEMS TO HAVE A MERCURY NUMBER BUT HAS BEEN WORKED BY MAZCO. I BELIEVE YOU ARE RIGHT THAT THIS MUST BE A MAZCO PROP. I APPRECIATE YOUR REPLIES.... GB....QUOTE]Originally posted by AnthonySS
Dear GB,

Most of us that have been running STV’s for some time will agree that a merc 14 ½” x 30” Cleaver is a choice/ favorite prop on an STV with and hi-perf merc. These props are low rake (+/- 18-22°). I have never seen a hi rake 30” Cleaver, by Mercury at least.

On the other hand, Mercs 32” Cleavers are hi rake (26-28°). I have never liked the use of hi rake wheels on my STV, They tend to provide too much bow lift and make the boat want to roll/lean to port with large torque compared to the low rake.

Your 28” Cleaver is certainly a low rake just by the way you say the steering load is light. I would stick with the low rake wheels on the STV, Try a 30” but not your son’s especially if you never have more than 2 people in the boat. What make is that 30” Hi-Rake.

Sincerely,

AnthonySS
[/QUOTE]

GB
07-31-2001, 03:58 PM
[THANK YOU FOR YOUR REPLY. MY SON'S PROP MUST BE THE MAZCO AND IS QUITE A HAND FULL AT THE HIGHER SPEEDS ON MY BOAT. MY STV IS USUALLY A CAKE WALK TO DRIVE OTHERWISE .... GB....QUOTE]Originally posted by Firewalker
I too have never seen a high rake 30 from merc, but I do know that the mazco cleave has a lot more rake, and as such more torque.
Side note, In my experiance what works on an allison does not work on an STV.

RT [/QUOTE]

AnthonySS
07-31-2001, 05:45 PM
Der GB,

Keep rockin in your STV and you are welcome for the replies...Always glad to help!

Check out:

http://www.stvowners.com

its still under construction, but you may find some interesting stuff for now!

Sincerely,

AnthonySS
STVowner

Way2Fast
07-31-2001, 09:26 PM
Bret Anderson at Merc Racing told me that Mercury 3 blade cleavers up to 30" have 15 degrees of rake and those over 30" pitch have 20 degrees. All 4 blade cleavers have 15 degrees. I don't know where all the other degrees of rake posted prior come from. Not a stock lab cleaver according to Merc.

AnthonySS
08-01-2001, 09:13 AM
Dear W2F,

I agree with Mercurys claims, but when we have actually measured some of the low rake merc cleavers, the rake was actually higher then 15°.

Just our experiences! Again our range was more in the 18-22°.

Sincerely,

AnthonySS

Raceman
08-01-2001, 09:01 PM
Anthony, how are you measuring the rake. I've never done it with the full size blades, but used to measure the old cleavers for the SSM's by just measuring the rear edge of the blade in relation to a line perpindicular to propshaft. I was told by one of the old prop guru's that I was foolin' myself that way. I guess it didn't matter enough to explore it, since we only had 2 basic options, but I'm curious anyway.

AnthonySS
08-02-2001, 12:01 PM
Dear RACEMAN,

I actually don't measure my rake. I leave that to my prop guy Harold. He has a device that he uses along with his pitchometer, called Rake Indicator. Its really cool and quite accurate. He takes his measurements along the cup line.

He tells me I can make my own using a combination square but I have never tried.

Sincerely,

AnthonySS

Markus
12-16-2005, 07:52 PM
I found this old thread when fooling around.

The rake data for Mercury cleavers was very interesting. Does anyone know the rake of other cleavers, e.g Mazco, Spinelli, Mach, etc?