1981 Montauk 17 Re-power

Optimizing the performance of Boston Whaler boats
Jason_in_Pensacola
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1981 Montauk 17 Re-power

Postby Jason_in_Pensacola » Mon Dec 27, 2021 10:56 pm

I plan to repower my 1981 MONTAUK 17 with a modern four-stroke-power-cycle engine. From my research, I conclude that a Yamaha F70 would be the best engine. At this moment, however, I cannot find any F70 engines at any local dealers--there are simply none to be found.

One dealer recommended the MONTAUK 17 be repowered with a Suzuki DF50A. He estimated the engine would cost $6,500, $1,000 for remote controls and other rigging, and $200 or so for installation.

Suzuki engines have a solid reputation; their price is competitive; the standard warranty is longer than on a Yamaha engine; the Suzuki engines use a timing chain instead of a timing belt; they are extremely fuel efficient; they are quiet; and they are available

I use my Montauk solely for fishing and trolling in Pensacola Bay and off the beach in the Gulf of Mexico. I only go out in fair weather on calm days. and I amnever more than about a mile off the beach. I want an engine that is reliable and fuel efficient. I do not particularly care about quick acceleration onto plane or top speed. I do not pull skiers or tubers. My lower back is susceptible to harm from any boat speed greater than 25-MPH in the normal bay chop. I could always add a hydrofoil to improve acceleration onto plane.. I am 49 years old, my height is 6-feet 20inches, and I weigh 205-lbs. My 14-, 12-, and 10-year-old sons usually join me.

The 1981 MONTAUK 17 hull weight is approximately 800 to 900-lbs, which is lighter than the current 150 MONTAUK which is rigged with a Mercury 60 FOURSTROKE engine. The Mercury 60 FOURSTROKE seems to give outstanding fuel economy on the 150 MONTAUK

Q1: is a Suzuki DF50a has enough power for a MONTAUK 17 if the engine had an added foil on the anti-ventilation plate and the proper propeller?

Q2: should I buy a DF60a?

Q3: will a Suzuki DF60a on a classic MONTUAK 17 give similar fuel economy to the Mercury 60 FOURSTROKE on the 150 MONTAUK?

Q4: will the in-stock Suzuki DF50a suffice for my intended use and typical boat loading for the MONTAUK 17?

Q5: should I hold out for the Suzuki DF60a?

Q6: will the DF50 that's currently in stock suffice for my intended use and typical load?

Thank you all for taking the time to read this and I look forward to hearing anything and everything anyone might be willing to say/offer.

ASIDE: I would like to say hello to everyone here. I have been browsing this forum for about a year, ever since I purchased my 1981 Montauk 17, and I find it to be a treasure trove of extremely useful information; for that I say thank you to all of you who've shared your vast knowledge and experience.

Thank you all for taking the time to read this and I look forward to hearing anything and everything anyone might be willing to comment.

--Jason

coachf
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Re: 1981 Montauk 17 Repower

Postby coachf » Mon Dec 27, 2021 11:43 pm

I have a 1977 17-footer with a 2003 Mercury 50 FOURSTROKE tiller-model with a hydrofoil. There is also a 110-lbs auxiliary engine, two batteries, several 15-lbs cannonballs, plenty of other fishing gear, and I weigh 230-lbs.

The top boat speed is about 28-MPH. I cruise off the west coast between 16 and 22-MPH, depending on the conditions.
Sometimes my son and his wife join me knocking cruise speed to about 20-MPH if the sea is calm

A fishing resort in Campbell River, British Columbia, uses 17-foot Boston Whaler hulls with 50 or 60-HP four-stroke-power-cycle engines.

At times, I wish my 17-footer had 60-HP, and when the current 50-HP needs replacement I will buy a 60-HP.

Some pictures of 17-foot tiller boats:
https://www.paintersresort.com/resort-experience/fishing

jimh
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Re: 1981 Montauk 17 Repower

Postby jimh » Tue Dec 28, 2021 8:26 am

From the Boston Whaler specifications for the MONTAUK 17, the minimum horsepower to put the boat on plane with a light load is listed as 35-HP. There is no doubt that with a 50-HP engine the boat should be able to get onto plane.

If the Suzuki DF50a and DF60a are engines built on the same displacement engine block, then I would not expect there to be a great difference is their ability to accelerate the MONTAUK 17 onto plane, nor would there be a difference in their weight. The ultimate top boat speed would likely be higher with the 60-HP than with the 50-HP, the acceleration may be slightly faster, and you may be able to use a propeller with an inch more pitch.

Engines generally are priced by horsepower, so the 60-HP will certainly be more expensive. Considering your typical loading of the MONTAUK 17 is four people, the 60-HP may be advantageous.

I have visited the fishing resort at APRIL POINT LODGE on Quadra Island, British Columbia, and seen their large fleet of 17-foot Boston Whaler hulls. They are not a MONTAUK model, and use tiller-steering. The seating is not the same as a MONTAUK. In general, the bare hull weight of those boats is less than a standard MONTAUK 17 model. When rigged for fishing and with three adults aboard, I would expect their weight is probably close to a standard MONTAUK 17.

Image
A Boston Whaler 17-foot hull custom configured for guided fishing at April Point Lodge. Photo by the author.

Image
A Boston Whaler 17-foot hull custom configured for guided fishing at April Point Lodge. Photo by the author.

There is a quite an interesting discussion about using 50-HP engines with a MONTAUK 17 in the archives:

Storm Story: July 17, 2006, Manitoulin Island
https://continuouswave.com/ubb/Forum1/HTML/013113.html

If your MONTAUK 17 boat is to be later sold, a MONTAUK 17 with only 50-HP would be a tough sell to the average boater who expects that hull to be powered with more like 70 to 90-HP and to exhibit very quick acceleration and respond like a sports car.

jimh
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Re: 1981 Montauk 17 Repower

Postby jimh » Tue Dec 28, 2021 8:47 am

Jason_in_Pensacola wrote:Q1: is a Suzuki DF50a has enough power for a MONTAUK 17 if the engine had an added foil on the anti-ventilation plate and the proper propeller?
See answers to Q4 and Q6 below.

Jason_in_Pensacola wrote:Q2: should I buy a DF60a?
See answer to Q5 below.

Jason_in_Pensacola wrote:Q3: will a Suzuki DF60a on a classic MONTUAK 17 give similar fuel economy to the Mercury 60 FOURSTROKE on the 150 MONTAUK?
Yes.

Jason_in_Pensacola wrote:Q4: will the in-stock Suzuki DF50a suffice for my intended use and typical boat loading for the MONTAUK 17?
Yes, but suffice suggests minimal compliance.

Jason_in_Pensacola wrote:Q5: should I hold out for the Suzuki DF60a?
With the qualification of having to "hold out" I infer that supply of the DF60a may be limited and delivery delayed. I also infer the cost is greater. I also assume the weight is identical to the DF50a. If you can tolerate the longer weight, afford the greater cost, and the weight won't increase, then the 60-HP only suffers from added cost. In other respects it will improve the boat.

Jason_in_Pensacola wrote:Q6: will the DF50 that's currently in stock suffice for my intended use and typical load?
Again, "suffice" is judged to mean meet the minimum; a 50-HP engine will be able to get the boat on plane as long as the propeller chosen allows the engine to accelerate into the engine speed range where it will produce 50-HP.

Using a anti-ventilation plate foil appendage may possibly help. I would hesitate to modify the anti-ventilation plate of a new engine before I even tested the engine and selected the proper propeller. The use of a foil appendage to the anti-ventilation plate of an outboard engine is usually most effective when the boat is marginally powered and has poor weight distribution, resulting in most weight being at the stern.

In the case of a MONTAUK 17 boat with a small DF50 engine, the engine weight will be quite reasonable, and since tiller operation is not intended, the helmsman won't be sitting at the transom. The fuel tank won't be at the transom. The battery can easily be moved to be under the console to further reduce weight in the stern.

The engine mounting height also affects the tendency for bow rise to occur during transition onto plane, as does engine trim. On that basis, I don't expect that adding a foil appendage to the anti-ventilation plate will be absolutely necessary to get a MONTAUK 17 on plane with a 50-HP engine.

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Phil T
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Re: 1981 Montauk 17 Repower

Postby Phil T » Tue Dec 28, 2021 12:48 pm

The information provided below is to assist you to make an informed decision. Ultimately, it is your choice. Take the advice you like and discard the rest.

I would like to address a key item.

The dealer is trying to sell you an engine he has in stock. .Be highly skeptical of his sales pitch.

If you review the archives, the majority of repowered Montauk 17 and the classic 16-foot hulls use either a 70-HP or 90-HP engine. Less than 10% are 50-HP or 60-HP.

Due to Covid, the production of outboard engines has been greatly affected. Demand from boat builders and the re-power market is 20 to 75% higher than typical.

If a dealer orders an engine now there is an approximately 5- to 12-month wait depending on the model. The F70 and all 90-HP engines have a six-month-wait, regardless of brand.

This has been going on for over 15-months.

For an engine in stock, many dealers are charging a premium compared to February 2020 prices. I have seen mark-ups ranging from $500 to $2000 depending on model.

The price offered for the F50 is "covid-priced." I use this term to mean, it has been increased to take advantage of high demand, low supply. I would speculate the price increase is in the neighborhood of $1,000.

Pre-Covid an F70 would cost close to $7,000 including tax, a Mercury 90 Fourstroke was $7,900.

Keep in mind, repowering a boat is the second largest boat-expense you will ever have. In some cases it will be more than the original price of the boat. (My repower in May 2021 cost more than the boat-engine-trailer purchase four years ago).

Do you need to re-power or just want to? If you don't need to, I would wait til the production and inventory problems settle down in 2023.

As for what brand and model to get, based on your planned use and your kids, who are going to grow up fast, I would order an 90-HP.

While you can't see it now, I have been where you are. Small kids grow up. In four years your kids are going to be 150 to 200-lbs heavier. Add some fishing gear, ice, fuel, food and maybe your girlfriend-partner-wife and a 70-HP is going to struggle. It is not about going fast, rather getting on plane and maintaining a cruising speed with a load. While you may not use it, with a 90-HP you will have it. If you go with a 70 and need more power--sorry.

As for brand, every brand (Nissan, Tohatsu, Suzuki, Mercury, Yamaha and Honda) have very good, efficient, quiet and reliable 90-HP models.

Talk to your boating friends and acquaintances to identify local service shops that provide quality service at reasonable prices. Find out what brands they work on.

Shopping for engine prices is like buying a new car. Be wary, get quotes in writing. Think of the dealer as a new car salesman. The key elements in my mind are engine features and price.

As for pricing estimates, look to pay (includes taxes) approximately:

Engines:
F70: $8,000
90-HP: $10,000 to $12,000; Suzuki will be the least expensive, and Honda will be the most expensive.

Rigging
Allow $1,000 rigging, wiring, network harnesses, throttle and shift cables, remote controls, key switch, multifunction gauge, etc.

Allow $500 for stainless steel propeller. Putting a $200 aluminum propeller on an $8,000 engine is like installing the wheels from a Radio Flyer wagon on a Ferrari.

Installation:
Allow $750 for engine removal, new engine installation, and water testing. If the transom bolt holes need to be redone, add $500.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Re: 1981 Montauk 17 Repower

Postby jimh » Wed Dec 29, 2021 9:34 am

Here is some information about weight and displacement of the several engines which have become the topic of this discussion. All weights are for long-shaft or 20-inch shaft engines. I have added this information because there is little value in discussing weights among engine without having any actual figures for those weights. Here is some data:

The Suzuki 50-HP and 60-HP engines are available in two distinct models, the A-suffix and the AV-suffix. All the engines are 0.941-liter three-cylinder engines. The DF50A and DF60A weigh 104-kg or 228.2-lbs.

The DF60AV has a larger gear case usually used on the DF140 engine. This allows the propeller diameter to be larger, up to 14-inches, and Suzuki says this results in increased thrust production. The DF60AV weighs 115-kg or 253-lbs.

The Yamaha F70A is a 1.0-liter displacement four cylinder engine; it weighs 114-kg or 251-lbs.

A typical c.1980 outboard engine for a MONTAUK 17 would have been an OMC 70-HP 0.9-liter three-cylinder engine that weighed about 250-lbs. An OMC 90-HP 1.6-liter four-cylinder engine would have weighed about 301-lbs.

A very popular 90-HP engine for re-powering 17-footers was the E-TEC 90-HP 1.3-liter three-cylinder engine; it weighed 320-lbs.

Jason_in_Pensacola
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Re: 1981 Montauk 17 Repower

Postby Jason_in_Pensacola » Wed Dec 29, 2021 10:17 pm

Thank you to everyone for your contributions and excellent information; I have lots of good data to sift through.

The dealer I mentioned with the Suzuki 50-HP is supposed to call me back to schedule a time for me bring in the boat for a written estimate [of the cost to re-power]. Later I will report on how my meeting with the dealer went.

I'm going to try for the 60-HP Suzuki, if I can get it. That sounds like the best compromise to a Yamaha F70. If anyone can think of a better compromise, please let me know.

OTHER COMMENTS

I will probably not wait for the Yamaha F70, although it is my motor of choice. MarineMax of Pensacola just told me they have a wait time of one to two years for a new, loose Yamaha outboard for repowering; the rest are all slated for new boat installations. The other dealers can't even give me a time frame. With the uncertainty and volatility of [the new outboard engine market], I feel better grabbing what I can, while I can, that is, a Suzuki 50 or 60.

The Suzuki 70 to 90-HP engine seem like they've got plenty of power, but I'm concerned about their size and 350-lbs weight. I've seen a few Montauk 17s with late-model 75 to 90-HP motors from the Orange Beach, Alabama, and Pensacola, Florida area, all the way east to Destin, Florida. Those engines seem visually to be too big for the boats and the boats' sterns seem to sit too low in the water for my comfort. The newer 170s have obviously been built for those 350-lbs engines but the older 17-foot hulls like mine definitely weren't.

TexasOutrage
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Re: 1981 Montauk 17 Repower

Postby TexasOutrage » Tue Jan 04, 2022 8:09 pm

I just purchased a 1987 Montauk 17 with a 1988 Yamaha 90-HP two-stroke-power-cycle engine that was original to the boat. I am doing a full restoration on the boat.

The Yamaha 90-HP two-stroke engine was the perfect-power and perfect-weight engine for the classic Montauk 17. The second best engine is the new Yamaha F70a.

I will eventually repower with the F70a due to its [less] weight compared to an F90.

If your current engine is reliable, I would wait for new four-stroke engines to become more readily available.