'63 Johnson QD-24b 10hp prop selection

[Fishy55]

I had two choices, 8 1/4x 8 and 8 1/4x 8 1/2. I ordered the 8 1/2 pitch. The motor is pushing a 14' Sea Nymph semi-v, it's a very lightweight boat, not sure of the model. I'm using it as a duck boat, so at times I've got several dozen duck decoys, shotguns, shells, two guys, and a deep cycle battery in the front for the trolling motor.

My question is, does the 1/2'' of pitch really matter? Would I notice a difference between the two while loaded down for hunting? More specifically, I bought a Michigan Wheel #012008. The other choice was a #012007. I couldn't find any marking on my ancient stock prop, I'm guessing it's a PJ-10 maybe?

Any input is appreciated, thanks.

 

[Fishy55]

Re: '63 Johnson QD-24b 10hp prop selection

Actually, I had 4 choices if I had purchased a prop from this site, but I found them a touch cheaper elsewhere. No hard feelings :S

 

[steelespike]

Re: '63 Johnson QD-24b 10hp prop selection

A 1/2" pitch increase is fairly large in a small motor or they wouldn't bother to make that step.
In 63 the motor came with an 8 1/4 X 8 1/2. That also appears to be the largest prop available today.The 8" appears to be more popular.With the load your carrying it would seem that the largest prop would be a poor choice.Your motor would be happier and more responsive if it revs freely.
Rpm range is 4,000 to 5,000.For best performance it should be propped near the 5,000 figure with a light load. An induction tach like the tinytach will help you check the rpm.
The 1/2" bigger pitch could be the difference in planing or not.
There are 14 footers that are small under 14ft centerline. and there are big 14s 14 or more centerline. A short narrow 14 will have a harder time planing a load than a longer wider 14 with a bigger foot print.
To get the most from your 10 be sure the carb opens all the way and it is in excellent tune.
Raise it on the transom just use a stick of wood to hold it up while you tighten the clamps.
Just be sure the clamps have a good grip.The less motor dragging in the water the easier to plane
and reach a max speed.Very carefull weight placement/elimination is important.Consider a 3 gallon tank. Motor will run about 3 hours at wot on 3 gallons whether loaded or empty.

 

[Fishy55]

Re: '63 Johnson QD-24b 10hp prop selection

Thanks steelespike, I've been wanting a 3 gallon tank now for a while. My 6.6 gallon is just too big, bulky, and heavy. I'm also considering replacing my old deep cycle battery with a slightly smaller and lighter one. This prop with do just fine for the rest of the summer while fishing. Perhaps I'll buy a 8 1/4 x 8 once duck season opens. I should have a spare on board anyways.