Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Current engine mount setup review

Posted by bsciance on 10/06/21 - 9:40 AM
#1

I'd like some feedback our current engine mounting setup as what I've read on this forum has me questioning it. I've been working on a couple small projects and when researching for those I stumbled across the suggested outboard mounting height, which is "3 holes up" or "second from bottom". Currently the outboard is mounted as low as it goes.

We bought the boat a year and a half ago. The previous owner repowered in 2016 with an Evinrude Etec 90. It appears that whatever shop did the repower mounted it all the way down. I've used the guide here to see how our mount compares: http://www.whalercentral.com/articles...icle_id=82

See photos on my personal page to view my current setup.

The lower blind holes are 6 1/2" beneath the upper, which is the same distance down that the green holes should be. However, when measured from left to right, the lower blind holes are 10 3/4" apart, not the 9 7/8" that the diagram shows.

When looking at the bolts in the lower blind hole, they appear to be threaded into the engine mount itself. If we were to get a shop to move the engine up to the 3rd hole, about 1 1/2", do you think the bolt would align and fit into the vertical slot along the lower part of the engine mount?

Unrelated question: previous owner included a brand new prop that they didn't put on. BRP Aluminum 13.2" with 19 pitch (BRP part no 0765184). I don't know anything about props but any thoughts on replacing current prop that is a bit dinged up?

Posted by Phil T on 10/06/21 - 10:03 AM
#2

In the old days, dealers installed the engines on the hull, not the factory.

Since 2000 owners and some dealers have discovered that engines can be mounted higher for better performance, less drag and better efficiency.

Typical installation used the "blind" holes for the lower bolts.

Your install is typical.

The repower installer was lazy and uninformed and re-used the lower holes instead of sealing the lower holes with plugs and epoxy and re-drilling the lower holes and then mounting the engine so that the upper bolts are in the 3rd hole counting down from the top. This would leave 2 holes open above the bolt. Hence, two (empty) holes up.

In addition the repower dealer supplied a cheap aluminum prop rather than the more efficient, durable and better performing BPR Viper 17" prop.

I would estimate as your boat is rigged, your WOT is ~37-40 mph rather than the 42-46mph. All due to improper install and poor prop selection.

Edited by Phil T on 10/06/21 - 10:05 AM

Posted by bsciance on 10/06/21 - 11:01 AM
#3

Thanks for the reply Phil.
I'll speak with my local evinrude mechanic to see about getting it raised up and set to the 3rd hole. I think I'd be comfortable doing the glass work and mounting but I don't have an engine hoist. There is a stainless steel prop on it now, not sure of its specs but it is pretty beat up probably from oyster beds in the Chesapeake Bay before we got it.

WOT ran about 33mph last spring, sounds like that can be improved. All summer I've been running it with family and small kids on board so haven't opened her up WOT since. I'll have to sneak out myself once I get the new EMM installed (which is a different issue).

Posted by Joe Kriz on 10/06/21 - 12:11 PM
#4

The lower blind holes should be filled and new lower holes drilled.

Measure twice inside and out to make sure the holes you drill will not interfere with the bottom of the splashwell including the washers in the link you showed. Green holes for sure but maybe the Yellow?

3 holes up is all the way up. Bolt in bottom hole for your motor.

All the way down is NO holes up which is what you have.

Edit:
See the holes on this members personal page he drilled for his new E-Tec.
https://www.whalercentral.com/infusio...ser_id=291

Edited by Joe Kriz on 10/06/21 - 3:35 PM

Posted by bsciance on 10/07/21 - 9:22 AM
#5

I've read through Evinrude's install and predelivery guide and it states on pg 48 "Generally, the anti-ventilation plate of the gear case should align with the bottom of the hull. Conventional V-hulls often perform well with the antiventilation plate approximately 1 in. (25 cm) above the bottom of the hull."

My current setup meets the recommendation above.
See photo on my personal page of AV plate and how it aligns with the bottom of the hull. It is roughly in line to an 1" above depending on tilt/trim.

With that being said, moving the engine mount up 1 or 2 holes would raise the AV plate up another 1" to 1 1/2" above the bottom of the hull.

Is there a general consensus that it would still be OK and engine performance would be good if my current setup is moved up 1 or 2 holes?

Current Prop is a Johnson/Evinrude SST 13 3/8 x 17

Edited by bsciance on 10/07/21 - 11:16 AM

Posted by Phil T on 10/07/21 - 4:00 PM
#6

The general consensus is 2 holes up. For E-TEC's 3 holes up.

For you, start with 2 holes up.

This is a Whaler owner tried and tested consensus. Note my paragraphs did not mention the engine manufacturer recommendation. They are conservative too. CYA mentality.