New prop installed...will test later today

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TPD211

Petty Officer 1st Class
Joined
Dec 31, 2003
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As a refresher......<br /><br />I bought a used 22' deckboat in Jan of this year.<br />It has a 1993 Evinrude 88 Spl. on it with a S.S. 14 X 13 prop.<br />My max WOT rpm's are 5000 at 28 mph on the dreamometer.<br /><br />As per various suggestions, I purchased a <br />Michigan Wheel # 011038 14 X 11 Aluminum prop (cupped) this past week from a local dealer. (they give me cost on my purchases). <br /><br />I took the boat out of the H2O Friday afternoon.<br />Installed the prop Friday night, cleaned up the old grease, put fresh grease on the shaft, installed the prop, new cotter pin, good to go.<br /><br />I also installed a inline fuel filter in the fuel line leading to the fuel pump as one was not there. The fuel pump filter (round one) is there. Put the mufflers on, started the motor, checked for leaks, none, good to go....<br /><br />I'm going to send the S.S. prop to C&B Marine to get it repitched, I will do this after the water test today to see how the change from 13 to 11 pitch works.<br /><br />Trigger out......
 
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TPD211

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Dec 31, 2003
Messages
360
Re: New prop installed...will test later today

Update:<br /><br />Boy, the aluminum prop su***xx.<br />WOT rpm's are 6100, way to high.<br />Speed at 5500 rpm's are now 23mph, a loss of 5 mph from the S.S. prop.<br />Hole shot is good, but I dont really care about it.<br />I'm putting the S.S. prop back on, I may have it repitched to 11 degrees. I'll see.<br /><br />I'm surprised at the change from 5000 rpm with the S.S. 14 X 13 to 6100 rpm with the alumiinum 14 X 11.
 
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ob

Admiral
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Aug 16, 2002
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Re: New prop installed...will test later today

Nice looking rig Trigger.Real clean.Can't really tell in the pics where the anti-ventilation plate would run in relation to the hull when trimmed level,but judging by what I can see in #3 pic there is bracket adjustment left to raise the engine.Before you have the shop reduce the pitch of the 14 X 13 SS prop ,I would experiment with the engine height and insure that it is placed at its optimal height setting.You'd be surprised at the Rs you can gain from reduced drag and reduced prop rotation load.OMC makes the 13" pitch SS prop for pontoon boat and larger rig applications such as yours in 13 3/4" dia.You could also entertain the idea of reducing the diameter of the SS prop instead of reducing the pitch.That coupled with any height you could gain on engine placement should not only improve WOT rpms but also pickup a few MPH.Good luck with whatever you decide.
 
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TPD211

Petty Officer 1st Class
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Re: New prop installed...will test later today

Thanks OB,<br /><br />The anti-ventilation plate is level or just above the bottom of the hull. I'm not sure how much higher it can go.<br />I sure was surprised at the 1100 rpm's it gained with the aluminum prop. I was expecting 400-500 or so, not 1100. :eek:
 
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ob

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Aug 16, 2002
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Re: New prop installed...will test later today

Remember Trigger that the even with hull or slightly above recommendation is just a rough guideline.Each setup is different.The only way that you can be assured of the engines optimal placement is to raise it a hole at a time and water test.The final placement should be at the highest setting where excessive prop ventilation will not occur 'on plane' at around 2/3 throttle while executing a tight turn.Once this is achieved , it will allow you make the final determination as to prop dia and pitch.Bare in mind that a doulble cupped three blade will bite better at the engines optimal setting than will a single cupped prop of the same dia and pitch.
 
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Dhadley

Supreme Mariner
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Feb 4, 2001
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16,978
Re: New prop installed...will test later today

You might want to re-think the deal about getting the SS repitched. Try a little different set up to gain rpms rather that add slip. Try raising the motor and test again with the SS prop.<br /><br />At least you know first hand -- for sure -- why some props are cheaper than others.
 
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TPD211

Petty Officer 1st Class
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Dec 31, 2003
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Re: New prop installed...will test later today

I tried the suggestion of OB. I had excessive blow out while turning at 2/3 throttle with the aluminum prop. I'm gonna exchange it for a 14 X 13 and use it as a spare.<br />I put the S.S. back on and will raise the motor a hole on the transon. It is at its lowest setting now. I'll play with the height before I send the prop to be repitched.
 
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steviecops

Chief Petty Officer
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Oct 3, 2003
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585
Re: New prop installed...will test later today

So do stainless props turn less RPM's than the same pitch and diameter aluminium props?<br /><br />I'm looking for a prop with less pitch to bring my revs up a bit and have a chance to buy a steel prop for a very good price. If it won't get as many RPM's as aluminium, I won't bother buying it.<br /><br />Can anyone advise me on this?<br /><br />Thanks<br />Steve
 
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TPD211

Petty Officer 1st Class
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Dec 31, 2003
Messages
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Re: New prop installed...will test later today

Steviecops,<br /><br />There are a lot of factors that affect rpm's.<br />Pitch of the prop is one of them. The design of the prop is another. Height of the motor is one also. <br /><br />I'm learning as I go along...... :) <br /><br />In my situation, the 14 X 11 aluminum prop turned a lot higher rpm's, but I lost a lot of speed also. There was excessive "slip" with the aluminum prop. <br />The S.S. prop, being a lot stiffer than the aluminum prop, does not slip as much, and therefore, has more "bite" in the water.<br /><br />S.S. 14 X 13 = 5000 rpm's 28 mph.<br />Alum 14 X 11 = 6100 rpm's 23 mph.<br /><br />I raised the motor a notch and will water test this week when I can. This is with the S.S. prop back on.<br /><br />I was able to exchange the aluminum prop for a 14 X 13. It will be here on Thur.
 
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TPD211

Petty Officer 1st Class
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Dec 31, 2003
Messages
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Re: New prop installed...will test later today

Water test results:<br /><br />I put the boat in the water after work today.<br /><br />S.S. 14 X 13 prop = 5100 rpm's & 29 mph.<br /><br />By raising the motor 1 notch I gained 100 rpm's and 1 mph. It sounded smoother thru the power band. It did not feel like it was lugging at all. The power was even, it cruised at 3800-4000 rpms and was smooth.<br /><br />I think I'll leave it alone now.<br /><br />Thanks to all for the support.
 
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