Whaler Central - Boston Whaler Boat Information and Photos

Posted by wellcraft on 03/26/13 - 4:42 PM

Hi guys, I have 1988 15' SS with a 1992 Johnson 70 and a 15 gal tank and I would like to get a new propeller. I don't know what I currently have other than is a SS prop. I was looking at the stiletto propeller and it seems to be a good prospective but don't know what size should I go with, would like to get a nice top speed. I think I was doing around 42 mph and the prop is not in great shape and I get some vibration while idling.
I found a used Stiletto Advantage 13.25" x 17p - excellent condition - zero dings or nicks on the blades for $200, is this worth the money, is it a good size for a 15 whaler ss with a 70 hp or should I look for something else?
what are mostly whaler 15 owners here use?

Thanks in advance.

JR

Edited by Joe Kriz on 03/26/13 - 5:39 PM

Posted by Tom W Clark on 03/26/13 - 8:32 PM

The 13-1/4" x 17" Stiletto Advantage would probably be OK. It *might* be slightly too little pitch for a 1992 Johnson 70 with its 2.42:1 gear ratio and 6000 RPM redline. 19" or 21" pitch props usually work best on 15 footers with OMC 70s.

$200 is a very good price so if it is not perfect, you can always sell it again.

Posted by wellcraft on 03/27/13 - 5:19 PM

Thanks guys for replying, I went to the boat today and check what I have, is a 13 3/8 x 17, what would be the best option in this case?
Should I go with a different prop?
The used prop I'm looking at is about the same size, so I thing I should try something different, although I don't complain about the current size I have, I just complain about the vibration because the prop is not in good shape.

Where is the best place to get a new prop with good prices?

Posted by dgoodhue on 03/28/13 - 4:01 AM

A common 13 3/8" x 17P stainsteel prop for Johnson Evinrude engines of that era is OMC SST. If you are running that prop on your engine, it doesn't have enough pitch and will over rev the motor. The 17P stilleto will have lower RPM than 13 3/8 x 17P OMC SST. (The 17P Stilleto will act like a 13 x 19P OMC SST)

How are you determing that your are doing around 42mph?
Do you have a tach on your boat?
Is you motor mounted all the way down (perhaps with blind mounting holes)?

With a stilleto prop, the motor should be mounted 3 holes up or as high as it can go. The 13 1/4 x 17P Stilleto will be about ~42mph at 6000 rpm. You boat/motor should go a little faster than that with the motor trimmed at WOT I would probably go with a 13 1/4 x 19P Stilleto, it will probably be just short of hitting 6000rpm. If you are often heavily loaded or do a lot of water sports, the 13 1/4 x 17P prop maybe a better choice.

Just as a side note the 3 cylinder 70hp Johnson and Evinrudes don't have a smooth idle.

Posted by wellcraft on 03/28/13 - 5:25 AM

Tom W Clark wrote:
So, if you found one for only $200, what are you waiting for?

Just trying to consider other options, like different size, might go with a 19 if isn't too much for the motor, found a few post with good results with them so I'm leaning toward 19's.

A found a place that sells them brand new with hub kits for not much money.

Posted by wellcraft on 03/28/13 - 5:31 AM

#10

Thanks for replying.
How are you determing that your are doing around 42mph? This was before rebuilding the boat and it had a speed gauge, not gps so I might be off.
Do you have a tach on your boat? Yes I do but can't remember the max at WOT.
Is you motor mounted all the way down (perhaps with blind mounting holes)? Yes, I was looking yesterday and I do have the blind mounting holes.

dgoodhue wrote:
A common 13 3/8" x 17P stainsteel prop for Johnson Evinrude engines of that era is OMC SST. If you are running that prop on your engine, it doesn't have enough pitch and will over rev the motor. The 17P stilleto will have lower RPM than 13 3/8 x 17P OMC SST. (The 17P Stilleto will act like a 13 x 19P OMC SST)

How are you determing that your are doing around 42mph?
Do you have a tach on your boat?
Is you motor mounted all the way down (perhaps with blind mounting holes)?

With a stilleto prop, the motor should be mounted 3 holes up or as high as it can go. The 13 1/4 x 17P Stilleto will be about ~42mph at 6000 rpm. You boat/motor should go a little faster than that with the motor trimmed at WOT I would probably go with a 13 1/4 x 19P Stilleto, it will probably be just short of hitting 6000rpm. If you are often heavily loaded or do a lot of water sports, the 13 1/4 x 17P prop maybe a better choice.

Just as a side note the 3 cylinder 70hp Johnson and Evinrudes don't have a smooth idle.

Posted by Tom W Clark on 03/28/13 - 8:19 AM

#11

The only way you will know if the 17" pitch or the 19" pitch is the best, is to try one. Since the 17" is available so inexpensively, I'd start there.

Remember folks, there are really two different OMC 70s, the 49.7 cubic inch 70 made from 1974-1985 with a 5500 RPM redline and then the 56.1 cubic inch 70 made from 1986 to 2001 with a 6000 RPM redline. Both use the same 2.42:1 gear ratio so what pitch works on one may not work as well on the other.

Posted by tedious on 03/28/13 - 8:28 AM

#12

The 17" Stiletto is an outstanding choice for that motor and boat - you should buy it. If you are most interested in top speed when running light, you may want to go up in pitch - but in order to do that you're going to need to raise the motor. I really doubt you're going to be able to overrev the 17 with the motor slammed all the way down.

Tim