New prop selection

[moombahighrider]

I have noticed that there is a ton of chat about choosing a new prop but I suspect guys aren't considering the change with the correct prerequisites.

When you guys are considering a prop change, are you looking at your WOT range with your current prop and adjusting from there? I don't see any one mentioning this and it is the one most important thing to consider. It doesn't matter whether you want more hole shot or top end, you must consider what your motor's WOT range is and choose a prop that gets you in the range and still fulfills your requirements. Maybe you guys are considering this, but I never see it mentioned. Just a thought...

As an example, on my new mojo, I got the OJ 15x13 prop with it. At Powell this weekend, I turned 10 hours and was able to go WOT. I found that the motor was spinning 5500 rpm. That is 100 rpm too high. The raptor 440 is supposed to run 5000-5400 WOT. So, at Powell, I need to re-prop. I'm thinking about going with an acme 15x13 that has some cup, which will bring the revs down 100 to 150 and get me in the right range. But I'm looking at a number of other options.

My normal boating lake is a few thousand feet higher in elevation that Powell and I have not been able to boat at that lake at WOT to see what the factory prop will do. I expect to have to buy a prop for Powell and one for my home lake. Not cheap, but it's a BOAT.

[moombahighrider]

Mods, can you change post heading to say prop instead of pro? Or delete completely- I created a new thread.

[rdlangston13]

I think it is important to note that you need to conduct your WOT test at the maximum weight you run. If you surf with 4,000 lbs of ballast, that's how you need to conduct the test. Not empty. Pretty sure that's how engine nut described it.


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[kaneboats]

I think you are kinda both right. I know I never run WOT with a full surf load. But I do run WOT with people in the boat and no ballast. I would do my check with that weight. I'd also check the RPM range with all ballast and people full at surf speed.

[PuraVida]

Dumb question: Doesn't the new raptor engines come with a rev limiter? I have a acme 2079 14.5 x 12 prop and seem to hit my rev limiter at half throttle when empty but struggle to get on plane with over 5000lbs of ballast and people. Does the WOT matter as much if you have the rev limiter? Or am I mistaken and the new engines don't come with a rev limiter.

[moombahighrider]

Dumb question: Doesn't the new raptor engines come with a rev limiter? I have a acme 2079 14.5 x 12 prop and seem to hit my rev limiter at half throttle when empty but struggle to get on plane with over 5000lbs of ballast and people. Does the WOT matter as much if you have the rev limiter? Or am I mistaken and the new engines don't come with a rev limiter.

I don't know if they do or not. Maybe it is limited to 5500 on the 440? That is what I got to WOT when I pegged it. If so, that will change what prop I should be looking at.

[smorris7]

Dumb question: Doesn't the new raptor engines come with a rev limiter? I have a acme 2079 14.5 x 12 prop and seem to hit my rev limiter at half throttle when empty but struggle to get on plane with over 5000lbs of ballast and people. Does the WOT matter as much if you have the rev limiter? Or am I mistaken and the new engines don't come with a rev limiter.

Something doesn't sound right. No way you should be at 5500 at half throttle with that prop. Any possibility the prop has been damaged?


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[wolfeman131]

effect of altitude?

[PuraVida]

No prop damage. Elevation is less that 1000'


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