How do you pick a prop?

F

Frank

Member
I smacked a rock today and dinged up my prop. Still usable but I should have another just in case. Now I don't see any #s on it, I guess I'll have to pull it off and see if they are hidden somewhere. But the question is this; I've been using this evinrude 9.9 on a small 14' glass over wood sneakboat. Now, until I can raise some cash, I'm using it on a 14' Duck Wrangler with 2 men. Definitely different hull and load. So how do you choose? Its working okay, its not planing but I really don't expect it to, but it might be possible to do better with a different prop design right?

So any help or suggestions?

Frank
 
Frank, I just went over this with a local mechanic. The prop #'s are located inside the cone of the prop. A flashlight and a rag and you should be able to find them. There are three different props available for my 99' Johnson 9.9..............One of them is a higher thrust pitch. I was told to go with this one and my power should increase slightly. But only slightly...............Good luck............Kevin
 
Thanks Kevin,
I guess mines not factory. I had to remove the nut and washer. Its a michigan wheel 012111. Now I went to their site and this is what I found;

Standard....................9 1/2 x 10...............#012111
14'-16' all load/ ski..........10 x 7..................#012112
Heavy Boat....................10 x 5..................#012113

My question is what constitutes a heavy boat?
I'm guessing that my 14' Duck Wrangler weighs 400lbs.
The Wrangler 15 is listed at 450.
And the 14'classic TDB is listed at 290.

There is also the question of rpm's. Since I don't have the equipment to test the rpm and I'm guessing that 400lbs isn't that heavy I think I'll go with the middle one. I think a 3 degree change in pitch is substantial.

However, I'm still open to any and all suggestions.

Frank
 
There is a pretty good explanation on www.midwestpropeller.com . For every drop in pitch there will be about a 200 rpm raise . A lower pitch number will let your motor speed up quicker while pushing a heavier load..thus getting the power out of the motor instead of lugging it..which is almost as bad for it as over revving. It's like trying to take off in 1st gear..or 3rd gear for an analogy. If you use your boat unloaded in the summer, you will want a steeper pitch or you will boil the water. When I had a 25 Mariner on my BB2, I'd use a 9.5 when loaded and a 11-13 when fishing. If I tried using the 9.5 unloaded, it would just sit and spin and tach-out.



Oh yeah, you want to pick a prop that will allow the motor to reach the recommended rpm's at wot (wide open throttle) designated by the Motor Manufacturer
 
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Frank,

I have a steeper pitched prop for an evinrude motor i no longer have. it's like new. if it will fit yours, i'll give you a good deal. i'll check the numbers tonight and i'll get a picture. i think it's the kind that does NOT use a shear pin.
 
Frank,

I have the Michigan 012112 prop. slight ding on one blade. I can load a pic tomorrow at work. i bought it to make my old 15hp turn faster. don't recall exactly what pitch it is.
 
Thats the baby. Post the pic or e-mail me and let me know what you want and how you want to ship.

Broadbillft@Netscape.net

Thanks,

Frank
 
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