more WOT rpm and prop selection

T

thosch

Petty Officer 3rd Class
Joined
Sep 3, 2001
Messages
90
1991 Johnson 90hp. on a 17.5ft Tracker deep-V alum. hull. Currently have a 2-piece 13.25x17 Hustler prop. With just me in the boat and no other cargo, I can get 5000rpm at WOT. With more people and some cargo, the best I can do is 4800rpm. I recently rebuilt the carbs, with no effect on rpm. Correct Champion plugs (77's), compression is 120 all cylinders. Recently did a decarbon by spraying SeaFoam into the carbs and letting it sit. Lots of smoke for a short time after that. Motor is running better than it ever has. I'm thinking a different pitch prop. Looking at the Hustler props on this site, I see a 14x13 that I'm thinking should get me up around 5500-5600rpm. My Clymer manual says operating range of 4500-5500, so should I be targeting WOT of around 5500rpm? Also going from 13.25 to 14' diameter is going to reduce the amount of space between the prop and the L/U just above the prop. Anyobdy have any experience or concern about that? Maybe a call to Hustler customer service would answer that.<br /><br />Thanks for any input/advice.
 
rickdb1boat

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: more WOT rpm and prop selection

Yes, you should shoot for the high end of the operating range.(5500 RPM)with a light load. And no, there will be no effect from the prop being "Close" to the case, as long as it does'nt hit. A 14X13 will work fine on your Motor! Your hole shot should improve greatly with the larger, yet less pitched Prop! Good Luck,
 
9

93evinrude

Petty Officer 2nd Class
Joined
Sep 9, 2002
Messages
154
Re: more WOT rpm and prop selection

With the move from a pitch of 17 to 13 you could find that your rpm's get a little high as there may be an increase of as much as 600 to 800 giving you 5600 to 5800 wide open with only you in the boat unless the prop has other differences such as more cupping etc..Unfortunately,it is hard to determine exactly without trying one.
 
rickdb1boat

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: more WOT rpm and prop selection

T.H.<br />I should have said " A 14 X13" Prop will "Fit On" your Motor just fine". I did'nt mean to indicate that it is the perfect one for your RPM band, although I still believe it will get you close! Just to clarify what I meant, so as to not lead you in the wrong direction. Good Luck,
 
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