1986 Montauk 17 Re-power

Optimizing the performance of Boston Whaler boats
Jeff65
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1986 Montauk 17 Re-power

Postby Jeff65 » Thu Dec 21, 2017 9:46 am

I have a 1986 Montauk 17 with a 1986 Yamaha 90-HP two-stroke-power-cycle outboard engine. I am considering re-powering with another 90-HP. I have concerns about weight and [acceleration onto plane] with a four-stroke-power-cycle engine.

[Are engine weight and acceleration onto plane with four-stroke engines] concerns or problems?

Looking at the E-TEC. I wonder what people's experiences are.

I am not sure what the transom weight [limits] are for older Boston Whaler boats. I hear [the transom weight limit] may be 386-lbs.

I know the newer [boats have a transom weight limit of] 410-lbs.

We do a lot of skiing and tube pulling. We load up [the MONTAUK] when going to the beach.

Thanks

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 10:20 am

Boston Whaler never published a specification for the maximum allowed transom weight for a 1986 MONTAUK 17 boat.

About 13-years ago I began a discussion about estimating the maximum transom weight that might be applied to older hulls. The discussion is archived and can be read at

Maximum Engine Weight
http://continuouswave.com/ubb/Forum4/HTML/002449.html

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 10:21 am

Jeff65 wrote:...I am not sure what the transom weight [limits] are for older Boston Whaler boats. I hear [the transom weight limit] may be 386-lbs.


Please give a citation for the source that states the maximum transom weight for your boat is 386-lbs.

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 10:25 am

Jeff65 wrote:..Looking at the E-TEC. I wonder what people's experiences are....

Are there any particular aspects of the owner's experience you want to specifically know about? I bought an E-TEC engine in 2009. My experience with the E-TEC engine has been extremely good.

Also, the choice of the E-TEC three-cylinder 90-HP engine for re-powering a MONTAUK 17 has been very popular. I suspect that more MONTAUK boats have been re-powered with an E-TEC 90 than any other engine, based on the frequency that re-powering of a MONTAUK with an E-TEC 90 has been described in prior postings to the forum.

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 10:42 am

Jeff65 wrote:...[Are engine weight and acceleration onto plane with four-stroke engines] concerns or problems?

The E-TEC 90 is three-cylinder in-line 1.3-liter two-stroke engine and weighs 320-lbs in the 20-inch-shaft model.

The Suzuki DF90A is a four-cylinder in-line 1.5-liter displacement four-stroke engine and weighs 343-lbs in the 20-inch-shaft model, or 23-lbs more than the E-TEC.

The Yamaha F90LA is a four-cylinder in-line 1.8-liter four-stroke engine and weighs 353-lbs in the 20-inch-shaft model, or 33-lbs more than the E-TEC

The Mercury 90 FOURSTROKE is a four-cylinder in-line 2.1-liter engine and weighs 359-lbs in the 20-inch-shaft model, or 39-lbs more than the E-TEC.

Note that the four-stroke-power-cycle engines all have larger displacement than the E-TEC. The larger displacement may compensate for the reduction in torque expected to be experienced in a four-stroke engine compared to a two-stroke.

I don't think a weight difference of 23-lbs to 39-lbs is particularly something to completely disqualify the heavier engine from consideration in re-powering a MONTAUK 17. You can compensate for a slightly heavier engine by moving the engine battery to the center console from the stern of the boat. That typically shifts more than 60-lbs out of the stern of the boat, and would be very effective in compensating for a slightly heavier engine on the transom.

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 10:54 am

I also recommend reading this prior discussion:

New Mercury 90 on a Classic MONTAUK
http://continuouswave.com/ubb/Forum4/HTML/008092.html

Regarding the Yamaha 90 two-stroke you have on the boat now, I think its weight is only 260-lbs, and its displacement a rather modest 1.1-liter. Any modern 90-HP engine you buy will be adding at least 60-lbs and as much as 99-lbs to the transom. I also expect that any modern engine will deliver better horsepower and torque than the old Yamaha 90.

Jeff65
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Re: 1986 Montauk 17 Re-power

Postby Jeff65 » Thu Dec 21, 2017 12:00 pm

Thanks jimh. I read all the posts so far and they are very helpful.

I called Boston Whaler in Florida and asked their advice on my older whaler with respect to transom and engine weights. They would not give any, but a voice from behind the person I was talking to stated my 1986 Montauk transom limit was 386-lbs. So I took it at face value.

Before I started my research on this topic, I had my heart set on a Yamaha 90 or a Honda 90, both four-stroke engines, But then I started learning about weight and torque. I want to make the right decision before spending a lot of money.

Then in my research I discovered the E-TEC, which is more like my older two-stroke engine and would have the same type of maintenance and winterization. I have always considered myself a Yamaha person, I guess, but think i'm leaning toward the E-TEC.

By posting I was just looking for some reassurance that I was doing the right thing. Thanks

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 1:15 pm

If you need to perform annual winter layup for your engine, you will love the E-TEC. You can winterize the engine in a few minutes. I just love that feature on my E-TEC. I run the winterization procedure, the engine automatically oils itself and shuts off. Then I just clean up the exterior, remove the cowling, give the engine a spray of some protective material (O.P.L from BRP for "Oils, Protects, Lubricates"), and that is about it. Every three to four years I service the water pump impeller. I change the gear case oil every two or three years. I only put about 50 to 70-hours of running time on the E-TEC per year. In nine season I think the engine has 450-hours.

Jeff65
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Re: 1986 Montauk 17 Re-power

Postby Jeff65 » Thu Dec 21, 2017 2:31 pm

Thanks. I did hear about that feature, and I have always done my own winterization. Also, I forgot to mention E-TEC is running a deal right now that includes a 10-year warranty option (if you buy the throttle, cables and gauges or something to that effect). That's huge. I am trying to get used to wrapping my head around an outboard engine brand other than Yamaha. Thanks again

jimh
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Re: 1986 Montauk 17 Re-power

Postby jimh » Thu Dec 21, 2017 2:43 pm

My advice in buying an engine is to be very selective in picking the dealer. Be certain you buy from a dealer that is completely authorized and completely equipped to service the engine. And be certain you like the guy and trust him; you will be giving him a big check.

There is no doubt you will be back sometime in the future for some follow-up work. Modern engines are generally too complex for home-brew repairs, and they often require computer connections to get data or implement new settings of parameters. Be sure the dealer can do this work effectively and honestly.

I bought an E-TEC, but a huge part of that decision was influenced by the dealer. The dealer I bought from (Lockeman's Hardware and Boats) has been selling Evinrude engines for over 90-years, has expert product knowledge, is a fully certified highest-technical-level-qualified dealer, and enjoys a very long with and is held in high regard by the manufacturer. I think if he happened to sell some other brand instead of Evinrude, I would probably have another brand--that is how much he influenced my decision. He is a great dealer.

And he only sells and services one brand, so he can really concentrate on that brand, be up to speed on that brand, and know how to service that brand. Also, with Evinrude, they only make one type of engine, the E-TEC, and all the engines are similar. That means the technicians can really get to know those engines. Dealers who sell and service multiple brands, and in those brands there are many different types of engines, must be working under much more difficult conditions, trying to be experts at so many different engines.