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Let me start by saying thanks in advance. Let me also say that the guy putting this motor on is not a marine mechanic but just happened to have an engine hoist as I do not.
So I am having this guy mount my new to me 2000 Johnson 115 Looper (I mistakenly said it was a 1996 in another thread) and he is saying that he thinks that the motor seems too short but he hasn't yet powered it up and trimmed the motor down, it is hanging on his hoist. I don't see how this motor could be too short as it is a 20" shaft just like the 48spl that came off. The second thing he is saying is that the bottom bolt holes are too low on this motor to clear the splash well. He started talking about altering the splashwell to make it work and I told him to stop so I could get some information. All of that got me thinking that:

#1- The motor will be plenty long enough with the trim all the way down, and
#2- That the motor should actually be mounted higher and it would clear the splash well problem and possibly make the boat perform better as I always see plenty of talk on here about that.
If anyone could give me some quick advice I would really appreciate it as this guy is 40 miles away and needs the motor off of his hoist to work on a car tomorrow.

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This is an FAQ.

The motor is the correct shaft length, 20" (Long) and should NOT be mounted all the way down on the transom but actually raised up off of it by about 2-1/4" using the lowest set of bolt holes in the motor upper mounting bracket.

This will allow the bolts to go through the second set of hole in the lower mounting bracket and easily clear the splashwell.

I am almost 100 percent certain the 48 as mounted using the auxiliary lower bolt holes (sometimes called "blind holes") and those will need to be filled and new ones drilled on the standard BIA layout.

See this article for a good visual:

http://www.whalercentral.com/articles...icle_id=82

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Thanks Tom. I did read that article after I posted the question. I sent you a PM on that too. I just wanted to make sure that this particular motor needed to be raised that high before I had him drilling holes. So when installed the "lip" that would sit on top of the transom should be 2-2 1/4" above the transom? So basically, he can just use the lowest hole on the bracket to have the motor raised and then drill the new lower holes as high as possible in the splash well? Thanks!

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Drill the Green Holes shown in the article. This will allow the motor to be mounted 2-1/4" up or 1-1/2" up. There is no reason for any 20" motor on any 16'-7" hull to ever be mounted lower than that with a modern propeller.

If you drill the yellow holes you will have clearance issues with the washers and the bottom of the splashwell. I never recommend drilling the yellow holes.

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I should add that if you drill the holes as I describe, not only will it work with your new motor, it will work with ANY motor now, or in the future, because the bolt hole spacing conforms to the industry standard BIA bolt pattern.

A lot of folks are afraid to drill holes in their Whalers, but this is a one time only chore and a very simple one at that.

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I think I understand. Raise the engine and put the top bolts in the lowest hole on the bracket thereby raising the motor, mark position of holes to be drilled for bottom, drill the holes and mount. And fill the old holes.

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Tom Clark has mentioned that better performance will be had if the motor is not seated all the way down on the transom using the lower "blind holes". I have a 1962 Nauset currently with a 2000 90 HP Johnson and I have always had all my motors installed utilizing the lower blind holes and the motor bracket resting on the transom. Right now I rarely go over 3200 rpm and cruise at a comfortable 26 mph. My question is, would I notice a significant performance if I were to raise the motor approx 2" as recommended. And what kind of performance improvement could be expected and where, in speed, fuel or both. Thank you in advance, Dino

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Tom when you refer to blind holes are you talking about bolting from the splashwell side with a machine bolt that threads into a threaded hole on the motor. That sure looks like what I have on my 1966 16' with a 1989 90 hp Yamaha. I have thought about raising it as you recommend but have not done so.

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mtown,

Yes, those threaded holes in the motor bracket are the "Blind" holes as you can not use nuts on them like the other mounting holes.

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Look: Tom usually knows what he is talking about, but I have a 1975 hull with a old 140 evinrude looper. My engine rest on the transom and I use the blind holes, the motor has been like that since I mounted in in 1985. I used bolts from the inside to the blind holes of my engine, and the upper two from the outside. I made an engine plate in the shape of a trapezoid for the inside of the splashwell for support. If I measure my engine the cavitation plate is one inch above the bottom of the boat (were it should be), Like I said Tom is usually right but I do not know for sure on this one...Take care...Ps hang the engine on the transom, have some pieces of wood made in 1/2 thickness and about 10 inches long by 1.5 inches wide, place them under the engine support until you find the correct height then drill your holes...

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I don't think so. An OMC V-4 mounted all the way down on the transom of a 16'-7" Whaler will have its A/V plate about one inch below the keel, which is about two inches lower than we like to see it with modern propellers. It was common practice back in the 1970s and 1980s, but today that mounting height is W A Y too low.

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Dino -- Yes, there will be a significant improvement in your boat's performance if you move your motor up and install a good stainless steel propeller. Among the benefits, you'll gain:

- Higher top speed
- Better fuel economy
- Less bow rise on acceleration
- Lighter steering effort
- Better grip in turns
- Reduced chance of propeller damage because the draft will be reduced.

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So my guy was going to raise the motor to the correct height but by doing so the old lower holes were going to be too close to the new ones so he put the motor all the way down and just bolted the top 2 in so I could pick the boat up and bring it home to mull over how best to go forward. While I was poking around I found that some previous owner had done the lag bolt approach. The holes were just filled with silicone. Somehow I missed this when I had the boat flipped and I was on a sanding marathon last year. So now I can either fill just the old lower holes from the inside and use the existing lag holes and call it a day (thereby having the engine lower than it should optimally be), Or raise it up which would require filling 2 sets of holes to be filled and 2 new lower ones drilled (this is the direction I am leaning). I am trying to decide what the best product to fill with would be and am leaning toward the west six-10 because it will static mix and squirt right into the holes without my having to pull the motor off again (thereby needing an engine hoist) and packing marine tex in there. Thoughts? I also have a prop question but will start another thread on that.

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For the love of Pete, what is it about filling a couple 1/2" holes that folks find so intimidating?

Fill the old lower holes, drill the new ones where they need to be and be done with it once and for all.

Yes, the motor needs to be removed from the transom to do this.

I suggest reaming out the old holes be sure they are free of silicone caulk, then glue in some wood plugs to fill the holes to fill the wood core thickness of the transom.

Fill the remaining depth with the putty of your choice, epoxy or polyester to the surface.

Then use a Forstner drill bit to cut a very shallow hole just through the thickness of the get coat and then fill that with color matched gel coat patch paste. Fair, buff and you're done.

You can also fill old holes with polyurethane or polysulfide caulk (I would not use silicone) but the old "blind hole" locations is close to the green holes where you want to be drilling so it is best to have real wood plugs making a structural fill there. Those holes do not need to be pretty; they are mostly covered by the outboard.

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It isn't that I am intimidated by filling holes, believe me I filled plenty when redoing the rig. My issue was that I don't have a hoist to remove the engine again and the guy that I know with one is 40 miles away and tied up working on cars for the next few weeks. But I will probably just wait and do it right. I do have a few other things that I can work on to get the boat ready, the next of which I am posting a new thread for.

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You don't need a hoist, just a come-along, a sturdy tree branch, and a bracket to attach to the top of the engine.

John K.