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What is the pitch speed ratio

sspogo

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I have an 86 35 hp Johnson and

I have an 86 35 hp Johnson and would like to get the best launch and top end for the river fishin that i do. The boat is a 14' Ski Barge and is made of fiberglass also; What is the benefits of stainless steel vs. aluminum?
 
"To be able to give You a more

"To be able to give You a more specific answer I would need Your model number. In 86 there were two different versions of 35Hp engines. One based on the 40/50 block (down-tuned)A-type, and one based on the 25/30 block (up-tuned)R-type."
 
"Barton, if you ever find a pr

"Barton, if you ever find a prop that will give you both a great hole shot and optimal top end speed, do pass the info on - alot of guys would like to know.

You usually can't get both from the same prop. A great hole shot (or launch) usually comes at expense of your top end speed and vice versa...."
 
"Barton...
Graham speaks the


"Barton...
Graham speaks the truth.
The reason you can't get both hole shot and top end out of one prop is due to engine RPM, or lack of. The smaller the pitch# of the prop, the faster it will spin for hole shot. It lets your engine RPM speed up faster when you're blasting off. Pitch # of a prop is similar to the thread pitch on a screw or bolt. It is the theroetical number of inches in length that the prop would screw itself through a solid (or water with no slippage)in one revolution. So a higher pitch # will travel alot farther in one turn than a small number. This is good for top end -- BUT-- it takes big hp to do that and to spin it at take off speed. A small pitch causes the engine, and prop to simply run out of RPM as you're at top speed. There are a lot of prop designs out there to try and find a happy medium. Variable pitch props,, 2,3,4,5 blades, cup blade designs. Just about anything if you look a far enough. An aluminum prop works great for most uses, especially in unknown water if there may be a chance of hitting something under water. Aluminum blades have a tendency to flex slightly straight under heavy load and lose performance, but are much cheaper than Stainless props, and more forgiving on lower end shafts and parts if they smack an obsticle hiding under the waves. The blades will fold over and .... cross your fingers. Stainless props are preferred for better performance as they don't flex straight as much (or at all). If it hits something underwater, you wreck the prop, bend the prop shaft, possibly spilt the bullit, bearnings etc... They are much more expensive to buy and to replace if they go missing all of a sudden as they are attractive to other people walking around the docks. Get a lock for it so it stays on your motor.

Wrench"
 
morten the model #is J35ELCND;

morten the model #is J35ELCND; does the diamiter of the prop play an important role along with the pitch now i have a 3 blade prop will a 4 blade help or hurt?
 
"Barton, these are some of my

"Barton, these are some of my favourite discussions. Yes, the diameter also plays a role. The greater the diameter (all else being equal) the more water the prop will push at a given rpm (overall square inches of prop blade pushing water).

You will find your choices for a 35 horse more restricted than say a 200 horse.

In general, if you want a great hole shot for water ski's, tubes, wakeboards etc, you would go with a 4 blade cupped prop.

A 2 blade will give you the best top end speed but would vibrate quite a bit. A 3 blade is a better choice for balance and top end speed.

You match the prop to your rig. A prop calculator can help find a starting point. You generally aim to get a match that will allow the motor to turn at about 200rpm less than the Maximum Wide Open Throttle rating for that model. That is where you develop maximum horsepower.

A 3 blade may allow you to do that using say a 12D13P (12 inch diameter/13 inch pitch -just an example)

A 4 blade cupped grips more water and creates extra drag because of the extra blade so you normally move down in pitch - so if the 12D13P 3 blade worked well, a 4 blade 12D12P would allow the motor to reach it's optimal rpm's. The 4 blade would get you out of the hole better, but you may lose 2-3 mph on your top end compared with the 3 blade...."
 
"For that engine the 4-blade t

"For that engine the 4-blade they later made for the 3 cyl 35Hp engine is far the best in all aspects. Not easy to get hold of, but worth a bit of effort.
Listed is only the 12"( 0176424) and 14" (0176425) pitch, but they were made even at 16" pitch."
 
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