Revist aluminum to SS prop

[crabman333555]

Thanks for you comments on my earlier post. I am confused as ever, but not so muchbecause of your post, as my vist to A/C boat show yesterday AFTER my original post. I talked with 5 vendors, including 2 Yamaha reps, and came away with differenct "EXPERT" opinions, including the Yamaha guys who even disagreed with each other. How is that for a headache? Again, my situiation:<br />22' C-hawk sport cabin, w/Yamaha 150 hp 3 blade aluminum prop (14 1/2 X 17) = 5100-5200 rpm's. Manual calls for 4500-5500 for 2 cycle motor 2003 model. They all agree, turning less than 5000 r's, loading engine, shortin life of motor. Over 5500 also no good, same results. ALL say same prop in SS will LOSE rpm's so different dia & pitch will need to change, but all say different specs. Now these people are "EXPERTS". Confusing huh? One Yamaha expert says I must be at 5500 exactly. BULL. So, now where do I find RIGHT scoop?

 

[walleyehed]

Re: Revist aluminum to SS prop

It's at the end of the other post.....<br />This isn't my first day on the boat, and most dealers don't test near the number of props I do.<br />The diameter issue can raise questions as to where to mount the engine height-wise for optimum performance. A direct replacement (if there is such a thing) in SS is most likely going to be "slightly" less diameter, and yet we can choose to go with a larger diameter if lower end performance is needed, which "may" require raising the engine a hole or 2, to maintain performance benefits we are trying to keep....do you see where I'm going with this???<br />There is no such thing as a "cover-all" prop.<br />Just removing the alum prop and installing an SS prop is not the answer in most cases. Look at my recommendation on the other post if "just changing over to SS" is all you want to do....If you want more, post back and we can get a bit more info and I'm 99% sure we can point you in the right direction.

 

[WillyBWright]

Re: Revist aluminum to SS prop

The one(s) that told you that a stainlness of the same pitch will turn fewer RPMs than an aluminum is simply wrong. You either misunderstood or you weren't talking to an "Expert", just a lowly Salesman.<br /><br />2-strokes like RPMs. Naturally if you run the motor too fast, things will break. If you lug them too much, then you'll do other internal damage. Neither of these are Wear issues. You're within the range at 5200 and probably worrying over nothing. The closer to the top of the range, the more usable horsepower you'll get. Any motor needs the proper RPMs to get the full rated horsepower. Running a 150 at less than that is developing less than 150 horsepower. At 5200, you're awfully close. (You didn't hear this from me but 150 Pro-Vs will run all day long at 6,000.)

 

[shep70057]

Re: Revist aluminum to SS prop

One misconception when switching over is that people lose R's. That may be so, but it's not because of the pitch on the SS. It's just that it doesn't flex as much as the aluminum. A smaller diameter prop may be the ticket. My Suzy 150 doesn't like those large diameter props.

 

[walleyehed]

Re: Revist aluminum to SS prop

The diameter has more to do with how the rig is set up... if you increase diameter- or decrease..-without adjusting anything else, the results may not be favorable.