1997 Dauntless 17 Re-power

Optimizing the performance of Boston Whaler boats
jackjax
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1997 Dauntless 17 Re-power

Postby jackjax » Sun Mar 28, 2021 2:02 pm

How would a Suzuki DF100b perform on 1997 Dauntless 17 Dual Console?

The original engine was a 1997 Mercury 115-HP two-stroke-power-cycle.

BACKSTORY
I moved to Houston from Florida. My house is very near a private boat ramp to Clear Lake thence to Galveston Bay. My 1997 Dauntless is just perfect here. The engine is not.

I can't go [boating] at night and then flush the engine due to noise ordinance after 8 pm. I always waited the next day. Now there is a water stream problem.

Very few mechanics know how to work on old raggedy Mercury two-stroke-power-cycle engines—a lost art now. I think the time to retire the engine is now--but not retire the boat.

I want to buy a quiet 115-HP engine [and a model specifically designated for] saltwater.

I read these older 17-footers won't be able to handle the weight of modern engines.

I am unsure what to ask. I have no experience re-powering.

Thanks
Jude
1997 BW Dauntless 17 115hp Merc

jimh
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Re: 1997 Dauntless 17 Re-power

Postby jimh » Sun Mar 28, 2021 4:26 pm

Modern engines generally are not sold in different models for saltwater and freshwater. All models are generally suitable for saltwater. Among modern engines there generally are no specifically designated offshore models.

Modern engines generally will produce far less noise, vibration, and harshness than your Mercury 115-HP 2+2 engine, which is really a 1970’s technology engine with no particular effort in its design with regard to limiting noise, vibration, and harshness.

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Sun Mar 28, 2021 4:27 pm

What is the weight of the original engine?

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Sun Mar 28, 2021 4:38 pm

Regarding what to ask about buying a new engine to re-power a 1997 Boston Whaler, I recommend you consider these questions:
  • Do you trust the dealer?
  • How many Boston Whaler 17-foot boats has the dealer re-powered?
  • How many years has the dealer been selling the engine brand?
  • Does the dealer have factory-trained technician with certification of attendance at factory schools or training centers?
  • How many loose new engines does the dealer sell every year?
  • Will the dealer provide on-water testing and propeller selection at no added cost if you agree to buy the propeller selected?

As you can see, all my questions are about the dealer to whom you will hand a $12,000 check. Choosing the right dealer is more important than picking a particular brand of engine.

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Phil T
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Re: 1997 Dauntless 17 Re-power

Postby Phil T » Sun Mar 28, 2021 5:13 pm

The 1997 Mercury 115-HP has a dry weight of 348 lbs.
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Re: 1997 Dauntless 17 Re-power

Postby jimh » Sun Mar 28, 2021 5:24 pm

What is the dry weight of the DF100b?

What is the dry weight of the 115-HP models?

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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Sun Mar 28, 2021 5:28 pm

jimh wrote:What is the dry weight of the DF100b?

What is the dry weight of the 115-HP models?

DF100b is 355lbs
Jude
1997 BW Dauntless 17 115hp Merc

jackjax
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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Mon Mar 29, 2021 9:15 am

jimh wrote:...As you can see, all my questions are about the dealer to whom you will hand a $12,000 check. Choosing the right dealer is more important than picking a particular brand of engine.


Thanks for the dealership idea. I was thinking of my mechanic doing the repowering and I research the engine (or he shows me one available in his garage). I sent quote requests to 2 dealerships, one of which is a Boston Whaler dealer nearby. I would love to know what they can come up with.
Jude
1997 BW Dauntless 17 115hp Merc

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 9:31 am

If the original engine was 348-lbs, and the Suzuki DF100b is 355-lbs, the added 7-lbs is nothing to worry about.

When re-powering it is common that the engine weight may increase. To compensate for more weight at the transom, some owners move the engine cranking battery or batteries out of the stern and to the console area. I don't know how that would work for a dual console boat like a DAUNTLESS. But moving a battery that weighs 50-lbs or more, or moving two batteries that weight 50-lbs, could compensate for any added engine weight.

If moving the battery is impossible, you could change to a LiFePO4 battery and cut the battery weight in half. But the battery cost would increase significantly.

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 9:38 am

Re buying a new engine from "a mechanic"--generally any new engine, that is, an unused, never-before-sold new engine in a crate, will include a manufacturer's warranty against any defect in original manufacturer for a period of at least three years and perhaps as long as ten years in some instances of special promotions. Generally any engine bought as new from an authorized dealer for the engine brand will require that the selling dealer install the engine and certify the installation process was done properly. Poor installation of a new engine on an old boat can often result in problems that manifest as engine trouble, when the real cause was poor installation. For this reason, manufacturers usually insist the selling dealer install the engine and certify it was done properly.

If you buy a used engine from your mechanic friend, there typically won't be a new-engine warranty, although perhaps some existing warranty coverage could be transferred if the engine would have remained under warranty with the original purchaser. For that to occur would depend on the details of the OEM warranty.

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 9:46 am

jackjax wrote:I have no experience re-powering.


Other upgrades to consider when re-powering an older boat are:

--new battery; modern engines usually require very strong batteries for cranking over; most modern engines must have a battery attached to start, that is, they cannot be pull started on a dead battery;

--new fuel lines and fuel-water separating filter; rubber fuel line hoses do not last forever, and some types, particularly hoses with a silver metallic outer cover are notoriously prone to decay with age; replacing fuel lines can be a prudent upgrade to prevent damage to a new modern engine; new filters are also a good preventative for fuel problems; here I assume the fuel tank has no big deposits of sediments and no leaks;

--new steering; if the boat does not already have hydraulic steering, upgrading to hydraulic from mechanical cable steering can be a very good investment, particularly as modern engines tend to be heavier;

--new engine instrumentation; modern engines all tend to use NMEA-2000 network data for engine instrumentation; replacing old analogue gauges with modern digital networked displays will be a nice upgrade; note that Mercury engines do not use NMEA-2000 and you must get their proprietary gauges; old analogue gauges are often brand-specific and won't work if a different brand engine is installed;

These are some ways fo rme to spend your money when re-powering. I liken it to buying a new car. Once you decide to get the new car, heck, you might as well get the leather seats, the navigation system, and the radar warning system. As soon as the wallet is open the money comes out more easily.

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 9:50 am

I have not commented on performance change if decreasing to 100-HP from 115-HP. If the two engines were properly rated and truly rated, then the horsepower decreases by a ratio of 100/115. Maximum boat speed would then decrease by a factor of (100/115)^0.5 or 0.93. That is to say, if the boat had a top speed of, say, 40-MPH with the 115-HP, then with the 100-HP the top speed would decrease by a factor of 0.93 to 37.3-MPH, assuming there was no change in weight. If weight increases, then speed decreases (again to the 0.5 exponent of the ratio).

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 9:51 am

Re buying a new, loose engine from a Boston Whaler dealer: my first thought is they might be the most expensive place to buy a new, loose engine--but you never know until you ask for their price.

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Phil T
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Re: 1997 Dauntless 17 Re-power

Postby Phil T » Mon Mar 29, 2021 10:23 am

Jack--sorry to surprise you but this is one of the worst times to repower. Due to COVID, demand for boats and new engines is off the charts. Boat production is already sold out for this year and part of next. Many owners expecting to just walk in and buy a new engine to re-power are waiting until fall or winter for the engine ordered to arrive. Prices are rising.

Don't get sucked into the craze. Smart thing is to wait, research, learn, and save your pennies. You should expect a re power to run $9,000 to $11,000 for a 90-HP engine and $12,000 to $14,000 for a 115-HP engine.

Don't worry about the flushing--it is not a concern. I know owners that only flush their engines once a year on haul out. Try using Salt-Away. http://www.saltawayproducts.com/KitPage.htm

Find a shop manual and do some work on your engine. Replace the hose from the block to the tell tale. Drop the lower unit and check the water pump impeller.
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jackjax
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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Mon Mar 29, 2021 10:28 am

Batteries are my concern, too. The boat batteries are on the port side console. However, I also have two batteries for the trolling motor on the starboard side console. I need to mention these to the dealers on their weight considerations.

One dealer mentioned that they have experienced with Montauk re-powering, I mentioned the 1997 Dauntless is not the Dauntless they know now.
Jude
1997 BW Dauntless 17 115hp Merc

jackjax
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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Mon Mar 29, 2021 10:35 am

Phil T wrote:Replace the hose from the block to the tell tale. Drop the lower unit and check the water pump impeller.


Thanks Phil, I am thinking of doing [repairs to] the lower unit myself. I don't remember any of my mechanics replacing the water pump impeller. Must be time now.
Jude
1997 BW Dauntless 17 115hp Merc

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Mon Mar 29, 2021 1:55 pm

I think the Suzuki DF115A weighs 412-lbs in 25-inch shaft version and 401-lbs in 20-inch-shaft version, based on

http://www.suzukimarine.com/Product%20L ... F115A.aspx

I think the transom height of a 1997 DAUNTLESS 17 is 25-inches.

Going to the Suzuki DF115 from your present engine adds 64-lbs.

It sounds like on the boat under discussion the batteries are already moved out of the stern. That means no more battery weight to take out of the stern. The only item left might be an oil tank for the present engine, but that cannot weigh very much, perhaps 3-gallons of oil at full at about 6-lbs-per-gallon. And the four-stroke-power-cycle engine "dry" weight does not count the 1.5-gallons of lubricating oil it will carry.

I don't see much other weight to remove from the stern.

The Yamaha F115 25-inch-shaft weighs 386-lbs. That saves 26-lbs from the Suzuki 115. They say it is the lightest 115-HP on the market--but I suspect you will be paying more for the Yamaha than you'd pay for the Suzuki.

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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Mon Mar 29, 2021 5:05 pm

Thanks Jim. I might consider 90 hp to cut costs. I remember I used to get max speed just over 40 mph. Now just 33 mph and I am fine with it. I am waiting for quotes and call back. I think I can ask smart questions now.
Jude
1997 BW Dauntless 17 115hp Merc

jackjax
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Re: 1997 Dauntless 17 Re-power

Postby jackjax » Sun Mar 13, 2022 10:33 am

Update: I got a call that Suzuki outboard arrived. The price is $15,000--I might as well give them my boat at that price. And a new dashboard will be an extra cost. I am staying with the original engine, the 1997 Mercury 115-HP outboard engine--it is durable.
Jude
1997 BW Dauntless 17 115hp Merc

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Re: 1997 Dauntless 17 Re-power

Postby jimh » Wed Mar 23, 2022 2:10 pm

Thanks for the update that the 1997 DAUNTLESS 17 boat WILL NOT be re-powered due to the $15,000 (or more) cost of a new engine (and mandatory accessories) which apparently is about the same figure as the present value of the boat.

I believe the discussion of the re-powering has now come to a natural conclusion.