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personal page updated
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| duf |
Posted on 08/29/13 - 5:44 PM
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i agree with Ritz, excellent topic for some basic, hanging your motor for the best results. I think the best thing i can do, since the motors will be broken in shortly, is shoot a video of where the A/V plates are in relation to waterflow, and post it. Will be interesting to hear the input, although its fairly easy to follow, you don't want them to deep, but with the same regard, not to high either disturbing the intakes that cool the motor.
More to come as soon as i can shoot the video, not worried about the break-in, its required i run WOT for intermittent period. Past that, and now, only can't run a prelonged time at a given RPM.
Duf
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| kamie |
Posted on 08/29/13 - 5:48 PM
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ritzyrags wrote:
This is very interesting data here thanks to Tom for disclosing his experience.
I am presently about to remount my Merc 150 25" to my new jackplate
The answer to my specific choice of holes to attach may lie in the above comments.
http://www.whalercentral.com/showuser...to_id=1644
Excellent topic.
For mounting on a jackplate you want to mount the engine so the AV plate will be at or above the keel when the jackplate is all the way down. That gives you the maximum adjustment.
Joe,
There is also a photo of my E-Tec AV plate at the correct height on my personal page.
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| Joe Kriz |
Posted on 08/29/13 - 6:16 PM
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kamie,
Your photo looks just like the one in the link I showed before.
And for the record. How many "holes up" are you as you don't say on your page ?
Edited by Joe Kriz on 08/29/13 - 6:17 PM |
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| Silentpardner |
Posted on 08/29/13 - 6:21 PM
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Thank you Tom and Joe! Your discussion here has educated me extensively. I have instructed my motor installation tech to install the new 300's on my 1989 Whaler 27 FC with Whaler Drive in the top set of holes. I have been searching for this information for a while, there is a giant void of information regarding engine mounting height on Whaler Drives, thanks for the information. That link in Joe's post is invaluable to me. I now have a clear visualization of what correctly adjusted engine height looks like.
Thanks to you as well Duff! Here again, your posting has led to more information than I bet you EVER expected that will help me a lot with important engine decisions :)
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| Joe Kriz |
Posted on 08/29/13 - 6:26 PM
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kamie, duf, Bill, Tom, and anyone else I missed.
Keep these things coming.
Other members need to know this.
Photos are great and make sure you tell us what boat you have, and how many "Holes Up" you are in the photo.
We have asked everyone nicely for the last 7 or 8 years, to use this diagram and describe how your motor is mounted in "Holes Up".
Please read the 3rd line in this article:
http://www.whalercentral.com/articles...cle_id=106
If we all use that terminology which is used many places around the Internet, we will all be talking the same language.
We had one member recently that didn't want to follow that and complained that he wanted to start his own language.
1X, 2X, 3X, 4X, etc. Sounds like a football team Jersey size.
What does X mean?
For that matter, what does 2 mean?
2 holes from the top or 2 holes from the bottom? Doesn't tell us much especially due to the fact that some motors have a different number of holes. As it stands now, some motors have 4 bolt holes and some have 5 bolt holes.
It doesn't matter how many mounting holes a motor has. 4, 5 10, 20, etc. (they may add some in the future, who knows?)
If a person says they are mounted "21 holes up", we know the bolt is in the 22 hole from the top. Not the bottom or the middle, but from the top.
So, more photos and more testing for some.
Those older Whalers with the motors using the blind holes and mounted all the way down, need to come up.
Edited by Joe Kriz on 08/29/13 - 6:28 PM |
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| BillDemers |
Posted on 08/29/13 - 6:41 PM
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So to sum things up your a/v plate in relation to the water is what we should be concerned and however many holes up or down your engine is mounted is just how we quantify the position. I suppose there are some known scenarios or combinations of boat/engine and mounting holes that are common. But in the end we use the holes to get the a/v plate in the right place.
That as some good info in the link, thanks Joe
BillD
1999 Dauntless 18' - 135 Mercury Optimax |
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| Silentpardner |
Posted on 08/29/13 - 7:06 PM
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We have asked everyone nicely for the last 7 or 8 years, to use this diagram and describe how your motor is mounted in "Holes Up".
OOPS!
Sorry Joe, I will have those 2013 Yamaha F-300, counter-rotating, 4-Stroke motors mounted 4 holes up on my 1989 Whaler 27 FC with Whaler Drive, or should I use "WD" instead of "Whaler Drive"? :)
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| Tom W Clark |
Posted on 08/30/13 - 7:07 AM
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...if I move my motors up an additional hole, what change will I see? Increased speed, better handling on plane, what's the advantage?
Duf -- Raising the motors that last 3/4" will probably give you another 50-100 RPM, a little higher speed, a little bit more fuel economy, reduced draft, better acceleration, lighter steering effort and maybe less spray.
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| Tom W Clark |
Posted on 08/30/13 - 7:13 AM
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...you don't want the A/V plate too deep, but with the same regard, not to high either disturbing the intakes that cool the motor.
That is a common misconception. In the context of typical outboards on Boston Whalers, it is impossible to mount a motor so high that the flow of cooling water will be reduced; the propeller will loose all grip long before the motor is so high the intakes aren't submerged. There just are not enough bolt holes to even come close to that point.
Outboards mounted on jackplates on very high speed watercraft *sometimes* need to worry about that, but not a Boston Whaler.
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| Tom W Clark |
Posted on 08/30/13 - 7:26 AM
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Thank you Tom and Joe! Your discussion here has educated me extensively. I have instructed my motor installation tech to install the new 300's on my 1989 Whaler 27 FC with Whaler Drive in the top set of holes.
Again, I suggest everybody read with more care. What I wrote on page 2 was:
Twin 25" shaft length motors on a Whaler Drive equipped 25 should be mounted as high as they can go.
This may, or may not, apply to a Whaler 27 Whaler Drive. I should also go further and say that this assumes the motors are mounted on the factory recommended motor spacing of 29-3/4"
Remember, when twins are mounted on a V hull, the spacing of them will, to dome extent, dictate how far down in the water the gearcases go. The closer together the motors are, the more hull there in front of each motor and the lower on the transom (or Whaler Drive) the motors will need to be.
If, for example, a pair of motors were mounted on a Whaler drive at 27" o.c., the motors are each about 1-1/2" closer to the keel and the motors will effectively be about 1/2" higher than they would be at 29-3/4" spacing. That needs to be taken into account.
It may well still be that mounting the motors all the way up is a conservative place top put them, but it should be considered.
Motors mounted in "the top set of holes" are mounted all the way down. You want the motors all the way up, or three holes up.
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| kamie |
Posted on 08/30/13 - 7:36 AM
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Tom W Clark wrote:
...you don't want the A/V plate too deep, but with the same regard, not to high either disturbing the intakes that cool the motor.
Outboards mounted on jackplates on very high speed watercraft *sometimes* need to worry about that, but not a Boston Whaler.
I never have to worry about it running and on my 18, but I do when i put the boat on the jetdock. If I get the right angle, i can launch the boat onto the doc so far that the cooling intakes are out of the water.
Joe,
It really depends on the jackplate. On mine, the engine is mounted 3 holes up and with the plate all the way down, it's still buried. I will have to measure but I think i had to raise my plate 3 any 4 inches. I have a Rite-Hite jackplate with an 8 inch setback. Next time i have the boat off the lift, i'll take a picture of the engine mounted to the jackplate.
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| Joe Kriz |
Posted on 08/30/13 - 9:31 AM
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Thanks kamie,
I forgot you were using a jackplate.
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| Silentpardner |
Posted on 08/30/13 - 10:27 AM
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This may, or may not, apply to a Whaler 27 Whaler Drive. I should also go further and say that this assumes the motors are mounted on the factory recommended motor spacing of 29-3/4"
The Yamaha 300's are going to have to be mounted at a 31" spacing between them instead of the original spacing due to the width of the cowling on them. At 293/4" spacing, the cowlings interfere with each other when steering. This wider spacing moves the motors away from the centerline of the hull. With the new 300 Yamaha mounted on the port side of the boat in the 1 hole up position, the cavitation plate was located even with the bottom of the Whaler Drive hull. By moving the mounting position to the required spacing of the motors, the cavitation plate will be about 1/2" below the bottom of the whaler drive hull (estimated). From previous comments here and in other Whaler forums, I have ascertained that I should be shooting for a position of the cavitation plate at about 1 1/2 " above the bottom of the whaler drive hull. By moving the mounting all the way up at 3 holes up, I don't think I can get the cavitation plate up to that height relative to the boat at the wider spacing between the motors, but it is as high as I can get them.
Am I thinking in the right direction here, or would you recommend starting lower, say at 1-2 holes up? The original motors were mounted one hole up at the 29 3/4 " spacing of the engines and seemed to be working well, although I did not observe where the cavitation plate was running during seatrial.
I will be using the Mercury Revoluton 4 props on the 300 Yamahas and it is my understanding that they work best mounted higher on the boat relative to other props. I really don't want to have to do a LOT of motor height adjustment on this boat, as I am thinking it will be a royal pain to get this done.
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| MG56 |
Posted on 08/30/13 - 12:08 PM
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SilentPartner, I find it is easier to find info by google carpetbombing the search. Once you set up a site search you can change the keywords. The info is out there, you just have to read and be a pest when necessary. It's too bad the other site is running off of Flintstone technology and this site doesn't enable PM's, but you can not beat the Whaler Family for getting help.
This whole thing about height is for one thing, straight line top speed. I like to F around and with a transom mount I can ventilate on hard turns. You are on a Whaler Drive with engines out wider than the norm. My seat of the pants guess is you want to be lower than the maximum possible height.
Read through the links below, it won't take you long to find someone with better info than mine.
https://www.google.com/#q=site:whaler...drive+prop
Edited by Joe Kriz on 07/29/16 - 6:44 PM |
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| MG56 |
Posted on 08/30/13 - 12:13 PM
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Oh, Silent Partner, how about tossing in a comma once in awhile? Make a point, make a paragraph. A block of text is hard to read.
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| Joe Kriz |
Posted on 08/30/13 - 5:25 PM
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Silentpardner wrote:
1989 Whaler 27 FC with Whaler Drive, or should I use "WD" instead of "Whaler Drive"? :)
Silentpardner,
We have a fairly complete Legend of Boston Whaler abbreviations that Boston Whaler uses at the bottom of the Personal Page sections.
http://www.whalercentral.com/viewpage...page_id=65
CC= Center Console
DC= Dual Console
SE= Special Edition
WA= Walk Around
WD= Whaler Drive
WT= Walk Through
(sometimes they use a dash - between the initials and sometimes a forward slash / . To conserve space, we use nothing)
There are a few more describing motor config.
OB = Outboard
SD = Stern Drive
IO = Inboard Outboard
IB = Inboard
Edited by Joe Kriz on 08/30/13 - 5:31 PM |
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| duf |
Posted on 08/31/13 - 1:11 PM
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Tom W Clark wrote:
...if I move my motors up an additional hole, what change will I see? Increased speed, better handling on plane, what's the advantage?
Duf -- Raising the motors that last 3/4" will probably give you another 50-100 RPM, a little higher speed, a little bit more fuel economy, reduced draft, better acceleration, lighter steering effort and maybe less spray.
I guess that's a no brainer (coma) that all the things you mentioned Tom are something i would like to induce on my boat (period) My plan at the moment (coma) is to pull the boat around Jan (coma) and while i'm working on the teak (coma) maintenance on the motors (coma) i'll have them raised to an additional hole (period) It will be interesting to post the results (period)
Duf
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