propping an I/O

(chadly22) · (chadly22) **Join Date: Apr 2007** 04-02-2007, 10:12 AM

I have a 21' marada i/o with a 5.7 mercruiser. I banged up my 19 pitch 3 blade and am looking to buy a new one. The mercruiser site is suggesting a Mercruisier "High 5" 19 pitch prop. Has anyone used these. I was thinking of upgrading to a 4 blade for better hole shot and lower planing speeds, but I think that 5 blade might be overkill. Has anyone out there changed from a 3 blade to 4 or 5 blade? If so, what's your experience?

(zo1) · (zo1) **Join Date: Aug 2002** 04-02-2007, 10:15 AM

I had a High 5 on our old I/O. Worked great! HIghly recomended. The only prop that I had used that wokrd better than that was the Land and Sea variable pitch prop but at a grand a piece it was a little to spendy for my blood when the first one got torn apart by a tree.

patxstar 04-02-2007, 11:29 AM

buy a new boat with a 4 blade

(sroot1) · (sroot1) **Join Date: Aug 2005** 04-02-2007, 12:49 PM

We have a 2000 190br with 5.0L that had a 19P Merc Vengence prop. It was ok to plane, but would ventlate easily when turning.
I put a 17P Hi-Five on and it made a huge differnce. Way faster out of the hole, easier to make speed adjustments, no ventilation and seemed to make the wake firmer less wash. I am not certain why the prop would change the wake but it did.
The Wide open throttle is right at the top of the range. But we did not buy this prop for speed.

(chadly22) · (chadly22) **Join Date: Apr 2007** 04-02-2007, 3:27 PM

No thanks Pat. I'm happy with what I've got (no payments

). How about aluminum 4 blades? I may just go for the "high 5", but the aluminum 4 blades are so much cheaper and if the performance is similar, I'd like to check those out.

(sroot1) · (sroot1) **Join Date: Aug 2005** 04-02-2007, 3:37 PM

Try E-bay Bass parts store $415.
I was able to demo a 19P and a 17P Hi-five on our boat. The 19P was better than the 19P 3-blade on maintaining speed but only slightly better out of the hole so I went with the 17P even tho the Merc. calculator said to use the 19P.
http://cgi.ebay.com/ebaymotors/MERCURY-HIGHFIVE-BOAT-PROPELLER-19-PITCH_W0QQcmdZViewItemQQcategoryZ26456QQitemZ32003 9587255QQtcZphoto

(chadly22) · (chadly22) **Join Date: Apr 2007** 04-02-2007, 3:46 PM

Thanks Scott, I''l check them out tonight.
Nice boat! Who did your swim platform?

(sroot1) · (sroot1) **Join Date: Aug 2005** 04-02-2007, 5:14 PM

I got the platform from:
http://www.swimplatforms.com/
It was a bit of money but it matches the gelcoat very nicely.
The guy that made it worked for quite a few years at SeaRay.
I plan on covering it this spring with Gator Grip for a little cushion.

(deltadave) · (deltadave) **Join Date: Mar 2005** 04-02-2007, 5:23 PM

I would go High 5. As I recall you do have to go down in pitch to compensate for the 5 blades.

(rallyart) · (rallyart) **Join Date: Nov 2006** 04-02-2007, 8:25 PM

Go stainless on the prop unless you are confident you are going to scrape the bottom often. You'll get less cavitation and a higher top speed.
I put on a Mercruiser 4 blade after trying the High 5 and thought it suited mine better. Some places will let you demo a prop. My 4 blade has plastic plugs at the base of the blades that you can drill or replace to allow exhaust to escape at low RPM. I drilled mine to almost a quarter inch each to let the prop slip more on launch. It helped some and I'm happy I changed out the 3 blade. I didn't lose any top speed and got a much better launch.

(bobbym) · (bobbym) **Join Date: Dec 2005** 04-02-2007, 9:55 PM

I used to have a 19 ft i/o and I went through a few prop types trying to get it dialed. This is after I had perfect pass too.

High 5 is the best but very expensive.
Four blade alum is a better comprimise.
Really not that different.

I did have a four blade composite prop with replaceable blades. Ok performance, but it blades seems to break for no reason.

With your 5.7 it might be better to go stainless high 5.

Top speed will be better with a four blade.