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View Full Version : Help me - Prop selection!



Patrik Sweden
04-26-2006, 01:44 PM
I bought my 22 Classic this winter, and today I took the first ride!!

But.. It wasn't so fast I thougt it would be.. 47.5 Knots, 60 MPH...:bawling: :bawling:

Boat facts:

Year: 1998
Engine: 350 MAG MPI
Bravo One

Engine hours: 140h..

I can't find what prop I have today.. but I know the previous owner didn't change from factory prop, what prop does it come with?

Just so you know... I love the boat!!!

mphatc
04-27-2006, 08:57 PM
Patrik,
I can't tell you what came on your boat, sorry.

On your props hub should be some numbers that may help us to ID the prop.
or they may also be stamped on the side . . ?

How many rpms was your engine turning at full throttle ?

Mario L.

MOP
04-27-2006, 09:16 PM
Patrik my 22 came with the 300 Tempest engine it was said that it made 300hp at the prop. I had a 21" 3 blade Mirage on it ran 61+, 60 is about all you can expect without modifications. 60 is a respectable speed plus the boat is more nimble with a small block then a big block and burns less fuel.

Phil

Woodsy
04-28-2006, 06:43 AM
Patrik...

Your out of luck... 60 is the best you can expect with that engine/drive combo. Most of the 70 MPH boats have an extra 100HP to play with.

There are few ways to to make your boat faster... an IMCO shorty lower unit, and a labbed prop. That combo should put you in the mid 60's.

Woodsy

Patrik Sweden
04-28-2006, 11:26 AM
:(

Ok, I just found out that I had 23P.. is it possible to run a 27P you think?

MOP
04-28-2006, 11:31 AM
:(
Ok, I just found out that I had 23P.. is it possible to run a 27P you think?

A 27 will be way to much prop it will overwelm your engine, even the 23 sounds like it is a bit more then you need. Like I mentioned in my post above same boat a 22 Donzi a little more power and was turning a 21 and getting 61, your engine should be turning about 4800 at full throttle you need to prop for that.

Phil

Patrik Sweden
04-28-2006, 11:35 AM
A 27 will be way to much prop it will overwelm your engine, even the 23 sounds like it is a bit more then you need. Like I mentioned in my post above same boat a 22 Donzi a little more power and was turning a 21 and getting 61, your engine should be turning about 4800 at full throttle you need to prop for that.
Phil

Hmm, ok, but my rpm shows 5200 at full throttle, I can't put on a 21 Pitch then..

Morgan's Cloud
04-28-2006, 11:56 AM
I've thrown this nugget out before and it's not too late to do so again ......
HAVE YOUR TACH CHECKED FOR ACCURACY BEFORE YOU DO ANY PROP TESTING !
there , I feel much better now :biggrin:
Steve

MOP
04-28-2006, 12:01 PM
Hmm, ok, but my rpm shows 5200 at full throttle, I can't put on a 21 Pitch then..

Like Steve said check your tach, with the 21 I was turning 5100 with a 1.5 ratio drive. You may have a 1.65 ratio drive, there is a tag on the side of the drive that will tell you the drive ratio. Between that and a spot on tach it should clear things up. But no matter how you cut it 60 is very respectable for a 5.7 300HP.

Phil

Patrik Sweden
04-28-2006, 12:21 PM
Ok! I give up:biggrin.:

But exactly how can I check the tach?

MOP
04-28-2006, 08:11 PM
Ok! I give up:biggrin.:
But exactly how can I check the tach?

Borrow or buy a small portable, but first look at he decal on the port side of the drive the drive ratio is there in very small print. Mercury may have decided the 1.65 drive was better fot this application, I went to the prop calculator and a 1.65 with a 23 seems to be close.

Prop calculator link http://www.rbbi.com/folders/prop/propcalc.htm

Patrik Sweden
04-30-2006, 12:16 PM
Now everything works fine.. 4900 RPM - 50.2 knots... (very windy..)

But I have a Vengeance 23P, do you think a Mirage 23P will change anything?

MOP
04-30-2006, 06:21 PM
My experiance with a Mirage was just fair, I am now running a Turbo 4 blade. The Turbo make the boat faster and much more stable across the board, several other up here have had good results with the Turbo. I still feel you pushing a Bravo 1 to 60 and above is very good with the 350 MAG, you may squeze a tiny bit more with another prop and more seat time. 48-5000 I feel is a good top RPM to stay within.

Phil