Prop Question

[b35w]

Looking to get a ss prop for a yamaha 90. How do I determine which is the right prop? Is it based on max rpms?

[Chuck the Duck Slayer]

What is your max rpm on your motor? Dont want to put a prop on that will max out your motor rpms at 3/4 throttle.

You want hole shot?
You want top end?
You want all around good prop?


Too many variables until you decide where you are at now versus where you want to end up.

[Redleg Camo]

Looking to get a ss prop for a yamaha 90. How do I determine which is the right prop? Is it based on max rpms?

to get the right prop you need to know how many RPM's you're currently turning at WOT. If you dont have a tach, get one. www.tinytach.com

no other way around it.

[b35w]

Runs 6000 at full throttle. Trying to get a little more speed. It's on a 17.5 ft Scout.

[Redleg Camo]

6k is about where you want to be. only way to gain speed is lighten the load and go up one inch in pitch. i wouldnt go any more than that.

what kinda prop you runnin? pitch?

[b35w]

Have no idea. It is the aluminum prop that came standard.

[Goin Coastal]

I hope it is a 4 stroke if you are turning 6k. If not you definitely need a new prop. If it is the switch to stainless will make couple MPH but don't expect anything drastic.go down one pitch from the aluminum to keep same rpm. Stay at same pitch and loose couple hundred ron but gain a little speed.

[b35w]

4 stroke

[Redleg Camo]

You need to turn 6k IMO. You might want to try a Yamaha Black Stainless prop in the same pitch you are running now. The yamaha black stainless semi cleaver style prop is one of the fastest props on the market. It has a little cup which will let you run a little higher and not blow out. That prop cost 3-400.00.

Powertech also makes a SCD3 prop. It is pretty similar to the yamaha black stainless. This prop will probably be a little cheaper than the yamaha.

It's just money. Cant take it with you.

[b35w]

If I gain speed but lose rpms, does that mean I lose power out he hole?

[Redleg Camo]

Typically a higher pitch will reduce hole shot but increase top end. There are a gazillion variables that go into the equation. weight, weight distribution, prop efficiency, motor height, etc, etc, etc....

If you replace the prop you currently have, assuming it is in perfect shape, with an identical prop that has 1" more pitch, you will lose 2-300 rpms. The speed you gain will be offset by the RPM's you lose which will most likely cause you to run the same speed, at a lower RPM, and lose a little hole shot.

What you need to do is find a more efficient prop that will keep you from losing RPM's.

An aluminum prop bends under stress. When you hit the throttle, it actually reduces the pitch of the prop under stress. that is why you NORMALLY go down 1" in pitch when going to stainless. Stainless doesnt give as much if any.

again, its just money. i have my share tied up in props.

Honestly, if i were you, i would either stay put, or try the yamaha black stainless semi cleaver, in the same pitch.

can you get the numbers off the prop so i'll know what pitch you're running and figure out how efficient your current prop is? they're either on the outside of the hub or inside behind the prop nut and washer.

[lil 2 sleepy]

What diameter and pitch are you running now? Then google propwizard.

I spun a hub on a prop 40 miles offshore Sunday, and learned more about props than I ever wanted to know yesterday.

Check with Skip's prop shop in Charleston. Great guy and he can set you up with whatever you need. He fixed mine in about 5 mins and has me rolling again.

[Love2labs]

I run the standard 13 1/2 x 15 aluminum on my G3 1860 during duck season. I turn 6K WOT and hit 37-39mph. Once the season is over, I go to the black stainless Yamaha 13 1/2 x 17 and turn 5700 rpm and run 43-45mph. I don't burn nearly the amount of oil or gas, and I still have one hell of a hole shot. I agree with D's T's. The Black SS Yamaha is the way to go. Keep in mind this is on a 2-stroke Yamaha 90.