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Posts: 4266
| I was having some problems with my rig and alarms going off constantly. I finally noticed that the rig came with a 14 pitch prop. Nice prop for coming out of the hole, but I can't run the motor at more than half throttle. Now that I've detected the problem, I need help with the fix.
What pitch are you guys running on 1760's? I have a 115 Optimax and need to know what prop I should get. I'm sure that there are options, and I'd like to get a good hole shot more than a 55 mph top end.
Who has suggestions for me?
Beav |
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Posts: 1764
Location: Ogden, Ut | 55 mph? You'll shoot your eye out kid...
S. |
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Posts: 4266
| Well I ran info through the Mercury site, and they recommend a 24 pitch four blade for the best handling and speed and acceleration.
I'll wear safety glasses  |
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Posts: 32953
Location: Rhinelander, Wisconsin | I don't think so, Beav. My 175 ProXS wouldn't turn a 24. I think you need a 19 or 20, probably a 19. That will give you about 1300 less RPM. |
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Posts: 4266
| Didn't seem right to me when I saw it, so I redid it a few times and it kept coming up 24.
What about the 4 blades? I've heard that you get much smoother handling with a 4 blade. |
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
To start off, I have to say I am a bit confused... If you have a 115 on the back, I don't think there will be any possible way to get to 55mph on a 1400 pound boat. A 150 might be right in that zone, though, so I am hoping that was just a typo.
Either way, I am guessing a 19 pitch would be about right as well. The 115 has a 2.07:1 Ratio, so turning max RPM of 5750 with 10% slip, I see about 45mph....that is about the best I would think any 115hp motor could get on a boat of that size and weight....breaking 50 would be extremely hard to do. But just for giggles, using a 24 pitch prop, it would come out to be right about 56mph.. I just don't think that is going to happen...
With the 150 hp, same numbers except gear ratio: 1.87:1 it comes up as just a tad under 50mph.
So....do you happen to recall what your RPMs were with the 14 pitch? and...could you verify the motor hp? That 115 just doesn't sound right...
Steve
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Posts: 76
Location: Kentucky | definitely need to have a close guesstimate on RPMS with the 14p. Also, I'd stay away from a 4 blade. All they do is add increased friction in the water. Stick with a 3 blade stainless. Is 1400 a good estimate of dry weight of that hull? |
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Posts: 32953
Location: Rhinelander, Wisconsin | A 4 blade Trophy will give you a better hole shot, a little better lift, and will run slower than the same pitch three blade Tempest or other Merc prop. Three blade will do everything you need. |
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Posts: 38
Location: Port Washington, WI | I am running the same boat and motor with a Mercury Vengeance prop on it right now. I am pretty sure it is a 17 pitch but I switched back and forth between 17 and 19 for a while so I am not possitive. My boat will run about 42 mph at max rpm on a good day. |
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Posts: 4266
| 115 Optimax, 14 pitch
almost 3000 rpms at half throttle-20 mph
if I trim it at all I bury the rpm needle. Best I could get trying to hold 5750 was <30 mph |
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Posts: 3508
Location: Elk River, Minnesota | Hi Beaver,
Definitely under-pitched. The prop is turning so easily that at max RPM, it's got tons of power but not a whole lot of forward thrust. With that rig, I would bet going to a 19 pitch get's you close...
Hopefully the dealer can get you a different prop to try?
You coming to the Vermilion trip in August? Would love to see the rig!!
Steve |
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Posts: 181
Location: Valparaiso, Indiana | Id run a 17 or 19...anything higher is to big for the 115hp Im turning 5250 rpm w the 19 pitch going 48-50mph gps reading |
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Posts: 4266
| Yes, my daughter and I will be up in August.
Looks like I'll be sporting a 19 pitch by then.
Beav |
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Posts: 4266
| Sounds good.
What kind of set up would need a 14 pitch anyway? |
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Posts: 208
Location: Sun Prairie, WI | pontoon boat
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Posts: 4266
| Where is a good place to list it besides here?
pontoonsfirst.com? |
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Posts: 507
| That prop will fit any of the 75 to 115 HP motors, so there's plenty of applications for it out there. |
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