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traveler

Determining RPM's at WOT

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Still trying to figure out prop/rpm issues...do I figure rpm's with the motor trimmed all the way down, or at some other position? I only turn 5000 rpm's trimmed down,( yamaha recommends 5000-6000) as I raise the motor the rpm's will come up, obviously if I raise it too high you can hear it rev as it isn't getting enough bite in the water, which isn't good for the motor of course. I understand theres probably a "sweet spot" where it will run it's best, but for determining if I have the right prop, where should I position the motor? It's a 150 v-max with a 21 pitch prop, btw.

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There should be a "sweet spot". Figure max rpm's where you would normally have the motor trimmed when under way, or at it's max trim up angle without losing performance. As you get more bow rise from trimming up, you should feel the boat speed up. When it hits the max top end speed, check your rpm's. They shouldn't be over your max limit or too low. Actually your rpm's at this point should be at or very near to the max recommended rpm's for your motor. If it's over and your hole shot is pretty good, you could probably go up in pitch a step. Just be sure to use a GPS for your speed along with your tach to get acurate results.

Also, if your boat seems like it needs more bow lift (still alot of motor trim left), check out some of the nicer stainless steel props with larger cupped edges. These props are made to help lift your bow and not blow out as quickly. They also help bite the water better when cornering.

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thanks Catman, I actually understand that:)

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Catman, any suggestions on props?

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Shoot, I don't know? I'm actually looking at new props for my boat right now, but I'm not sure what I'm gonna get yet. It's tough trying to pick the right prop. I don't want to waste $300 or more! If it's possible, the best thing to do is try em' before you buy em'! Find a dealer that sells props around your area and ask if you can return a prop if it doesn't work. Some dealers will let you do this, if they know you will buy the right prop from them when you find it. Then you can see what prop suits you best under all conditions. Also if your looking for more speed and a higher pitch prop, check out the props with "PVS" holes, (I think thats what they're called). Anyways, the holes add more rmps at take off by areating the water so you can get on plane quicker, and don't affect top end performance. As for actual brands, I'm not sure, but a good starting place would be at a bass boat forum. These guys are always talking about top of the line props and how to get better performance. You'll find all the top brands listed and then you can look up more info on the different brands. Of course, unless you have a bass boat with a big honking motor, your not ganna want to get the higher pitch props those bass boat guys are running. But atleast you'll know some good brands to look at.

Good luck with your purchase.

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