Whaler Central - Boston Whaler Boat Information and Photos

Posted by garrett007 on 04/05/09 - 7:02 PM

I just rebuilt and installed this 70 hp, 1990 Johnson VRO on my 1989 sport 15. Previous motor was a Evinrude 48 SPL. Used same transom motor mount holes. The bottom of the anti ventilation plate on the 70 hp is 1/2 inch below the bottom of the boat. Thought about moving it up, but would have to redrill bottom holes. If I move it up one hole on bracket, I go up 5/8 inch. Any thoughts on this? I think if I am slightly higher than bottom of the boat, I should be ok.

More photos are on my personal page, "Everglades Whaler"

Gary

Edited by garrett007 on 04/05/09 - 7:06 PM

Posted by Joe Kriz on 04/05/09 - 7:12 PM

The holes are actually spaced 3/4 inches apart.

Not sure about 15' models but take a look at this article.
http://www.whalercentral.com/articles...icle_id=82

You may need to go up 2 holes which would be 1 1/2 inches up.

Posted by garrett007 on 04/05/09 - 7:21 PM

Thanks Joe. I'll check it out.

I've always had my motors mounted with the anti ventilation plate level with the bottom of the boat. The higher you go, less drag. If I go up 1 1/2 inches will there be a problem with cavitation?

Could I go up 2 holes on the bracket, take it our and test it with two through bolts, before I start drilling the bottom ones? Is the transom stong enough?

Gary

Posted by Joe Kriz on 04/05/09 - 7:25 PM

If you could raise the engine 1 hole, and then drill the lower holes, you would be much better off. This way you could still raise the engine.

However, you must make sure that you could drill those yellow colored holes and not interfere with the interior splashwell. That is the problem on some models.

I'd like to hear from someone else who drilled the yellow colored holes on your year 15' model just to make sure.