1989 150 Yamaha

[MikeSchaper]

I am looking to up grade my current prop. I have a 1989 Yamaha 150hp OB. It is on a 89 Lund Tyee 1850. The current prop is aluminum and the only stamping on it I can find is 23-m. Is this a 23 pitch prop?

I am looking to get more top end out of it. I currently get about 42-44 MPH @ 4300 RPM at WOT. I am thinking I should get closer to 50 MPH. The max WOT rpm is supposedly 5500. I currently get a better then average hole shot and just want some more top end with out damaging the motor.

Also if anyone knows what spline I should have it would be helpful. Does the diameter make a hugs difference? I am new to this whole prop selection thing and want to make sure I do it right. A fella in town is selling a OMC prop #
14 1/4 X 21+, 15 spline, part # 38992 just curious if it would fit. Only wants 125 for it in mint shape.

Thanks a ton in advance.
MIke

 

[MikeSchaper]

Re: 1989 150 Yamaha

No body ?

 

[JB]

Re: 1989 150 Yamaha

Wrong forum, Mike. I will put this in the Prop Forum for you.

 

[hwsiii]

Re: 1989 150 Yamaha

Mike, I need to know the gear ratio for your motor to help you. But I can tell you that you are lugging that motor and keeping it straining all the time, wearing it out very quickly. And that 21" Pitch is not close to what you need.

H

 

[45Auto]

Re: 1989 150 Yamaha

But I can tell you that you are lugging that motor and keeping it straining all the time, wearing it out very quickly.

The motor is 20 years old, has probably had that same prop on it the whole 20 years, and apparently still runs fine. Exactly what is your definition of "quickly"?????

 

[Dhadley]

Re: 1989 150 Yamaha

A 23 would seem a bit stiff for that set up. However we should probably check the tach while we're at it. My guess is that you'll end up somewhere in the 19" range but let's verify the tach first.

 

[Dhadley]

Re: 1989 150 Yamaha

BTW - an OMC prop is not a direct replacement as far as fitting on the shaft. There's a number missing from the part number but that 21+ is an older SST.

 

[hwsiii]

Re: 1989 150 Yamaha

45Auto, you must have purchased that motor when it was NEW, you know so much about it. And by the way you must think it is good to run your motor at 1,200 RPM below maximum WOT. I wish you luck with yours too.
I show he needs an 18" Pitch if it is the same model prop and if the gear ratio is 2 to 1, and that will raise the RPM to about 5,200 and maybe he can raise the motor a little bit as well.

H

 

[MikeSchaper]

Re: 1989 150 Yamaha

Would an 18 get me more speed also? How can I verify the gear ratio? I thought the lower the pitch the less top end you got. I am slow on this stuff. By no means a boat wizard when it come to the prop. Are we thinking the 23-m means I have a 23 on there now?

Thanks again fellas

 

[hwsiii]

Re: 1989 150 Yamaha

Look in your manual for your gear ratio, and I show the 18" pitch should get you to about 42 MPH. But your RPM will be real close to what it should be. Dhadley knows much more than I do about picking the right brand and model of prop for a particular boat than I do, so listen to him. And yes it appears you have a 23" pitch right now.

H

 

[MikeSchaper]

Re: 1989 150 Yamaha

So I will not gain any speed then. I will just not lug the motor as much? I get 43 to 44 now on gps and on my speedo. The gentleman I bought it from says he got 50+ with the stainless he used to have on it.

 

[Rancherlee]

Re: 1989 150 Yamaha

I think 50mph mgiht be a stretch but you can get close. My Grandpas old Tyee 1850 with a Yamaha 130 V4 runs out at 43-44mph on the gps with a stock Aluminum prop, you should be able to get 2-3mph better than that with 20more HP and V6 grunt. Lund boats are not speed demons and 50+ mph is hard to come by with a Deep Vee aluminum hull.

 

[Dhadley]

Re: 1989 150 Yamaha

Your gear ratio depends on what model 150 you have. Mine has a 1.86, some have a 2:1. The other thing is to make sure the motor is running properly. If you have 1 cylinder not pulling it's fair share it could be costing 400-500 rpm on top. Then look at set up. Too much drag can be costly too.

Not often will going to a smaller pitch gain speed but you're so far off it might. With a good prop that turns more rpm you might gain lift which means less drag which means more rpm & speed. Look at something like the Turbo Vector. 14 1/2" diameter, good lift, can run fairly high (again, less drag).

The M series props are Yamaha props built by Turbo.

 

[MikeSchaper]

Re: 1989 150 Yamaha

you are thinking a 18 or 19 in a 14 1/2 diameter? Ill have to get some numbers off my motor to see gear ratio. I want to ensure I make the right purchase for my motor.

 

[Dhadley]

Re: 1989 150 Yamaha

The Vector in a 19 would be a good choice I think. Let me know if you need help locating whatever you decide on.

 

[MikeSchaper]

Re: 1989 150 Yamaha

Will do. And thanks a ton. One more question. WOuld I gain anything, or what would be a better choice? 3 blade or 4 blade?

I used the prop wizard tool that some one suggested on this site and it came up with a 19 for water sports and a 21 for speed. I am getting more and more confused by the second.

 

[Dhadley]

Re: 1989 150 Yamaha

Actually I'm super impressed with the Turbo Ultima 4. I might be inclined to go with one on that boat if it were mine. Great holeshot, excellent mid range and faster than an ordinary 3 blade on most boats that use props in this pitch range. You'll probably be able to raise the motor too.