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1986 Montauk 17 with 2007 YAMAHA 70 Prop
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| edsasso |
Posted on 12/10/15 - 4:49 AM
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I just bought this boat and I plan on re-doing the boat with my daughter. With that said, I want to keep her safe. Safe to me means slow, so speed is not important to me at all. This boat has the stock aluminum prop and I want a prop that does not totally kill the top end, but I want it to be able to pull up a wakeboarder or two without issue. The boat will be loaded with approximately 100 lbs of fuel, 500 lbs of people and 200 lbs of gear on top of the listed weight of the hull and motor 1200 lbs. That totals 2k lbs and I think that is about the heaviest it will be…
Thoughts
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| tedious |
Posted on 12/10/15 - 7:47 AM
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If you'll excuse the shameless plug, I think the Stiletto Advantage 1 in size 13.25x15 I have for sale in the classified's Motor section here would do you very nicely. It is an outstanding prop for the classic 70 triples, and I have the correct Yamaha hubkit too. Stilettos are not made any more - they were too good a deal!
I base that recommendation on my very positive experience running the same prop in a 17 pitch on my 15 when it was powered with a Johnson 70, which is almost identical to your motor. I have found that Montauks usually drop down about 2 inches in pitch compared to 15s.
I would be happy take the prop back if it doesn't work for you, with you covering the shipping of course.
Tim
Edited by tedious on 12/10/15 - 7:50 AM |
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| Phil T |
Posted on 12/10/15 - 10:08 AM
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We have had two or three very detailed conversations in the last few weeks regarding the Yamaha F70 and selecting the appropriate propeller.
Tedious has been a integral player and his advice is spot on. Given that the Stiletto is no longer made, I would take him up on his offer.
In addition to the prop selection, you should review engine height. Almost all motors installed are mounted too low.
There are two ways to check you motor's height; bolt holes and the measurement of the anti-cavitation plate in relation to the keel.
There are 4 holes in the top set of the engine bracket. If the motor is sitting on the transom, the bolt is in the top hole. It is recommended that the motor be bolted to the transom using the 3rd hole. This is described as 2 holes "up", meaning two empty holes above the bolt.
TOP ........Bolt position
0 -----> If bolt here, All the way down
0 -----> If bolted here, 1 hole up
0 -----> 2 holes up
0 -----> 3 holes up
Edited by Phil T on 12/10/15 - 10:09 AM |
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| tedious |
Posted on 12/10/15 - 2:20 PM
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Just to clarify - I found the Stiletto Advantage to NOT be a good fit for my current F70, which is why I am selling it. In a 17-pitch, it did work very well on the 1989 Johnson 70 that was previously installed.
And yes, I, too, would be skeptical of someone recommending the prop they happen to have for sale - but I can't figure out how to not sound like a shady used car dealer, so I'm just being honest about it.
Tim
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| mtown |
Posted on 12/10/15 - 2:28 PM
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hey tedious I am interested in your prop but can't find the classified motor link you refer to.
Mtown
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| Joe Kriz |
Posted on 12/10/15 - 2:35 PM
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mtown wrote:
hey tedious I am interested in your prop but can't find the classified motor link you refer to.
Mtown
Look under "Outboard Motors For Sale".
http://www.whalercentral.com/forum/in.../index.php
His is the 5th post down at this time.
Edited by Joe Kriz on 12/10/15 - 2:38 PM |
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| edsasso |
Posted on 12/13/15 - 6:15 AM
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I ran the boat today and I got more information.
The boat at WOT ran 30 MPH fully loaded at 6100 PRM.
I have on it the stock aluminum prop 13.25x17 - k
Seems like I need a lot more prop to get all the performance....
One more thing, I have a long shaft motor mounted all the way down.
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| Phil T |
Posted on 12/13/15 - 12:09 PM
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While your RPM's are good, speed and mounting position are not.
Get your mounting corrected and retested before changing the prop.
Raise the motor 2 holes, re-test and report back.
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| Perichbrothers |
Posted on 12/13/15 - 10:23 PM
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It amazes me how many outboards are hung way low.
There is such a performance difference in those two holes.
TP
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| tedious |
Posted on 12/14/15 - 5:00 AM
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edsasso wrote:
I ran the boat today and I got more information.
The boat at WOT ran 30 MPH fully loaded at 6100 PRM.
I have on it the stock aluminum prop 13.25x17 - k
Seems like I need a lot more prop to get all the performance....
One more thing, I have a long shaft motor mounted all the way down.
It's hard to say exactly what you need for a prop yet. Right now, you have two issues - an old-school aluminum prop that is slipping a lot, and your motor is hung too low.
Was 6100 as fast as it would go at WOT, or did you back off the throttle to avoid over-revving? What was the trim setting?
However, the previous posters are correct - first thing is to raise the motor a couple of holes. It does not cost anything except some of your time - no sense buying a prop to fit your current configuration.
Tim
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