Engine for classic 13-footer

Optimizing the performance of Boston Whaler boats
remarksf
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Engine for classic 13-footer

Postby remarksf » Wed May 15, 2019 8:09 am

I use a 13-foot Boston Whaler boat for short trips, and maybe some tubing or waterskiing with skinny kids. I have a choice between two engines for my [13-foot Boston Whaler boat]:

    --a 1982 Evinrude 35-HP electric start and no pull start, and
    --a 1989 Johnson 25-HP with electric start and pull start.

I am very new to boating.

According to data from NADA each engine weighs 114-lbs.

Q1: Does both engines weighing the same make sense?

I plan to pull off the engine by myself, then put the engine on a beach wagon to my yard when beached. Weight is relevant.

Q2: Is lack of pull start a concern?

Q3: Would the expense of buying the pull start and a new engine cowling be worth the value to have a pull start?

Reliability is important to me, and if electric breakdowns are common enough that pull starts can be handy, that would matter to me.

Q4: is there any reason not to buy the 35-HP?

Thank you very much.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Wed May 15, 2019 10:31 am

A1: In many cases two-stroke-power-cycle engines of different horsepower using carburetors are mechanically identical other than very minor changes in the carburetor and its jets. These minor changes account for different horsepower rating.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Wed May 15, 2019 10:33 am

A2: electric starting is very convenient but requires use of a large starting battery. Pull starting requires more strength than young children might possess. A well-tuned and well-maintained engine should start easily. Problems with electrical starting systems can occur, but, as with any electrical-mechanical device, if the battery, wiring, and electrical system are well-maintained there should not be any chronic problems.

It is common for small outboards with electric start to also be able to be pull started. I recall a 1976 50-HP engine I owned with electric start. Under the cowling there was a pull starting cord in a pouch. When I acquired the engine in 1997 the pull starting cord appeared to have never been used. That 1976 engine is still in use. I am in daily contact with the new owner. I believe the pull starting cord still has never been used.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Wed May 15, 2019 10:35 am

A3: because the cost of the new pull starting gear and a new cowling is unknown to me, the value of adding pull starting to an electric starting engine as a function of its cost cannot be determined.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Wed May 15, 2019 10:37 am

A4: using 35-HP on a 13-foot Boston Whaler will be near the maximum power (40-HP). The boat will be very fast, should have plenty of reserve power, and should easily accelerate under load.

The 25-HP engine is newer than the 35-HP engine, and it already has the dual starting feature you seem to want.

In my experience with a 13-footer with 25-HP the performance with two adults aboard was satisfactory.

A consideration for the future is the use of the boat by your children. A boat with 35-HP and a youngster driving alone may be imprudently fast.

remarksf
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Re: Engine for classic 13-footer

Postby remarksf » Wed May 15, 2019 10:50 am

Thank you very much Jimh

All very clear and helpful points; nearly all signs point to 25hp and you raised a few that I hadn't thought about. I think I'm really leaning towards that one; part of me wanted to make sure I am not being stupid in HP, as rule of thumb is "get a bit more HP so you are not underpowered". We are a light family, all 4 of us combined are 400 pounds, and we do not mind being slower if we pack a few more kids in, as it is a pleasant 2 mile trip to where we typically go.
Main concern is reliability and not breaking down, unable to start motor and get yelled at by whole family, particularly in first year boat ownership. Pull start seems to help that, and avoids electric breakdown as well as less gear as can ditch the battery, less to go wrong.
Once again, thank you very much and enjoy your summer!

Yellowjacket
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Re: Engine for classic 13-footer

Postby Yellowjacket » Fri May 17, 2019 9:22 pm

When I was a kid we had a 13-footer with a Johnson 40--the maximum power--but the boat wasn't all that fast. It did about 34-MPH. We'd lock the throttle wide-open and the boat was very stable. The boat didn't do anything silly even with a bunch of 15-year-old kids in it.

It might have gone faster with a taller propeller. We mostly used the 13-footer for water skiing and it wasn't propped for top speed. We were skinny kids and the Whaler with a 40 was about the perfect ski boat for three or fouro skinny kids. With a 25-HP you couldn't use it for much other than pulling a tube. We used to have two or three 100-lbs kids in the boat and we skied all day long

If you have young kids and they want to tube the 25-HP will do the job. But if you want to do any skiing, and for sure pulling up someone on a slalom ski, you're going to want more than 25-HP. Even a 100-lbs kid on a slalom ski will pretty much stop a 25-HP if he cuts hard.

If I were you, I'd get the 35-HP and use a propeller for 32-MPH top speed--should be about right. The boat won't be too fast and it would be a nice rig for skiing. That was our experience.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Sat May 18, 2019 8:29 am

If the primary purpose of your family owing a boat is to be able to slalom water ski at 32-MPH and allow the skier to make extremely hard turns, look for a used c.1980 Mastercraft 19-foot inboard boat available for around $5,000 to $6,000. The Mastercraft will be a much better boat for towing a slalom water skier that must make extremely hard cuts or turns.

A 13-foot Boston Whaler is an open skiff with remarkable stability, durability, and utility.

If a primary goal in boat ownership is to satisfy a 15-year-old male offspring that the family boat is really fast, then put the largest engine you can find on a 13-footer, get really good insurance, and turn those teenagers loose.

Yellowjacket
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Re: Engine for classic 13-footer

Postby Yellowjacket » Sun May 19, 2019 12:23 pm

If you're really bothered about going too fast you can just adjust the throttle cable on the 35 so that it doesn't open all the way.

What you can do is just select a prop that does 30 mph at the max rated rpm. That's a fine top speed for a 13 foot Whaler. Then, to prevent the motor from over revving at wide open throttle set the throttle cable adjustment and the throttle stop so that it doesn't over rev the motor with the lower pitch prop. With that setup you'll still have more torque at lower speed and be able to pull out a skier easily and the boat with that prop will hop right up on a plane even with a full load. Those are things the 25 will never be able to do.

If later on the kids get older and everyone gets heavier, you can just open the throttle more to keep the performance level you want.

If you go with a 25 you don't have that option. You're going to find that you're running wide open almost all the time that you have 3 or more in the boat.

As you've noticed the 25 and the 35 weigh the same and in most cases these are really the same motor with a smaller carb to limit the power. If you use the throttle stop you're doing the same thing, you just have the ability to adjust the power to match your needs if you decide later that you want more power.

remarksf
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Re: Engine for classic 13-footer

Postby remarksf » Mon May 20, 2019 9:09 am

Thanks to all.

I think either engine would be okay for us. Kids are still young, primary purpose of boat is more transport than sport (we will never slalom; kids are 5 and 10), but all things being equal wanted the idea/ability to potentially do some fun amateur watersports in the coming years. To the extent we get really into them, we could upgrade to a more dedicated boat.

Less worried about going too fast; I think these are now similar enough in some ways that I need to see which boat/engine package are a better fit overall, each seems to have pros and cons but either could work for us; neither is a big mistake. We are a small (and light) family who is pretty slow and safe, so 25 would not be way underpowered for us, and the ability to go no battery is appealing. A 35 gives us more flexilbiity if we bring guests (the idea of the boat is primarily a way to get to an amazing beach so bringing a few friends albeit crowded may still be fun for all).

I really need to get a better understanding of what shape each motor is in and that may be the decision-maker -- the 35hp I can do a test drive but the owner knows little history about (he is very trustworthy but got it from someone without the into); the other I can only get a start on the trailer, which gives me more risk.

jimh
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Re: Engine for classic 13-footer

Postby jimh » Mon May 20, 2019 12:55 pm

Don't worry too much about the future. If your family really enjoys boating as a family activity, you'll be getting a bigger boat very soon.

If your family becomes very enthusiastic about slalom water skiing and wants to cut very sharp corners on one ski while being towed at 32-MPH or more, then you will get a boat more suited for that sort of use than a 13-foot Boston Whaler skiff.

The 13-foot Boston Whaler is a great small boat, and many people have had one in their family for 50-years, but as a 13-foot open skiff the Boston Whaler cannot be everything for every person for every use. For some uses there are specialized boats that will be better than a 13-foot Boston Whaler.

If your family boating sustains and grows into a wonderful family recreation, I am sure you will find that you will need something a bit larger than a 13-foot Boston Whaler. But until you do, enjoy the greatest small boat ever made.

gman87
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Re: Engine for classic 13-footer

Postby gman87 » Fri May 31, 2019 2:03 pm

I have a 13' that my dad bought new in the late 60s. Originally we had a 35 Johnson on it, unsure of year, and as a teenager , we use to ski behind it without any problem. I've got a 2005 25 Johnson on it now and it still goes plenty fast for flats fishing but probably would be a slug to pull an adult up skiing whereas the 35 would have been ok.

remarksf
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Re: Engine for classic 13-footer

Postby remarksf » Fri Jun 07, 2019 10:09 am

Very close to buying this package-- the 35 HP 1982. Boat (1983 Super sport) in great shape and engine seems very good for its age (sale is contingent on full water test next weekend). The seller is great-- passionate about whalers and has had dozens of all types.
1) Given my inexperience and the fact that the majority of my trips are with young kids, over a shallow bay, to destinations 2-3 miles away, how much of a good idea is it to get a trolling motor in order to prevent getting stuck if engine problems (in order to ensure a happy family so I can keep boating)?
2) If I choose to get a trolling motor, which mount is easiest for someone who may not be that handy? (I have searched this forum and many of the previous discussions were for particular questions/mounts in the past)
Thanks

Jefecinco
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Re: Engine for classic 13-footer

Postby Jefecinco » Fri Jun 07, 2019 10:26 am

We always have a paddle aboard our 1981 Sport 13. It is adequate for traveling short distances if the engine fails. The more stamina you and your passengers have the more adequate the paddle becomes.

I don't believe mounting a trolling motor on a 13 foot boat as back up power is a good idea. The effort and expense of such a project could be better used to improve the reliability of the main engine.
Butch