15hp on a 14' Alum too heavy?

jonaddis84 · Oct 8, 2009

Hi all. I have an old (1950's) 14' Aluminum boat that was left to me by my grandfather. It has a 1972ish 9.5 Johnson on it which Im having problems with. The boat originally had the 3 wood seats in it and that was it.

Recently I installed a flat deck to the boat from the rear seat forward, complete with storage lockers etc. It also carries two marine batteries for the trolling motor and other electronics. I would guess that the boat weighs about 4-500lbs by itself, no motor or fuel tank. Right now when the motor seems to be running right I can only get 8mph MAX with just one person in the boat (according to gps).

Im looking into a new outboard for it and wonder if I should just look at around 10hp like a late 80s 9.9 merc? Will that thrust it to around 15mph if its running right?

Or I found a 2007 Honda 4stroke that fell off the boat for dirt cheap it just needs a new camshaft according to the seller. Do you think a 15hp (around 100lbs) would be too heavy for the boat? I have to guess the 9.5 only weighs around 60lbs as I can carry it one handed.

Thanks for any help.

cwhite6 · Oct 8, 2009

Re: 15hp on a 14' Alum too heavy?

I would personaly look for a little older two stroke 15hp. Most of them are pretty indestructible and a lot lighter than a 4 stroke. Also, if the motor feel hard enough to need a camshaft, there may be other issues with it that may not be obvious right now. I know plenty of folks with 15hp on 14' jon boats and they work just fine. Especially with all that extra weight on there.

WIMUSKY · Oct 8, 2009

Re: 15hp on a 14' Alum too heavy?

I had an 18hp Evinrude, '71, on a '70 14' crestliner with 4 bench seats. Worked great. I'd stay away from a 4 stroke too because of reasons already mentioned.

jonaddis84 · Oct 8, 2009

Re: 15hp on a 14' Alum too heavy?

Good point. I have been racking my brain trying to figure out how falling off the trailer could mess up the cam and not anything else.

I did find a 15 Johnson: Orginal owner. 1980 ,Ready to go, great shape .tuned-up ,new waterpump,hoses ect.great shape.tilt lever, burns low octane unleaded gas , best offer best offer

cwhite6 · Oct 8, 2009

Re: 15hp on a 14' Alum too heavy?

From what I have heard those older Johnson are hard to kill as long as you take care of it.

BWR1953 · Oct 8, 2009

Re: 15hp on a 14' Alum too heavy?

Maybe pix and dimensions would help us figure out your HP needs. For example, my little 14.5' aluminum boat is rated for 35HP.

Any way for you to get us more info?

Shizzy · Oct 13, 2009

Re: 15hp on a 14' Alum too heavy?

True. my 68 Alumacraft FD is rated for a 40HP, but similar sized boats can be rated for only a 10-15HP.

SeaNymph Man · Oct 13, 2009

Re: 15hp on a 14' Alum too heavy?

15 hp on a 14 ft. aluminum boat should be plenty. Stay away from four strokes,..may be too heavy for that older boat. If the Johnson motor
you found was taken care of,it will do the job. Though I am no fan of
Mercury outboards,...I guess if you had found one that ran right and
started when you want it to,not when it wants to,...you probably would
not have gone wrong with one of them,either. I am an Evinrude guy
myself,and have an 18 HP Fastwin from the '60's on a 1973 Sea Nymph
14R boat rated for 25 HP. It runs great!

erie_guy · Oct 14, 2009

Re: 15hp on a 14' Alum too heavy?

My 14' MirroCraft is rated for 25 HP; although I power it with a 9.8 HP 2-cycle Nissan because of a 10 HP limitation on the reservoir in which it operates. I as well would be cautious of the weight of a 4-cycle my 9.8 only weighs about 50 pounds.

A 15 hp should push your boat close to 20 MPH if the engine is running OK. I still have a 12' fishing boat with a 8 HP Nissan that runs 24 mph (gps) with only me and a concrete block in the bow for ballast.

Best of luck with your boat.
Sounds like you will give your granddad's boat a good home.

erie_guy
Port Clinton, OH

dan t. · Oct 14, 2009

Re: 15hp on a 14' Alum too heavy?

dont be so sure a 4 stroke is that much heavyer,I push my dingy with a 2006 merc 6 hp 4 stroke, it weighs 53 lb,it replaced a 1981 merc 4.5 hp 2 stroke which weighed 56 lb. a friend of mine runs a 25 hp Yamaha 2 stroke on a 14 ft Springbok,,works great,not over powered at all

reelfishin · Oct 15, 2009

Re: 15hp on a 14' Alum too heavy?

I would take into consideration the amount of freeboard and the transom height too before deciding whether the heavier 4 stroke would be a wise choice.
I have a 14 1/2' Grumman with super tall sides but a 15" transom height which is rated at 25 hp, but I found that even a modern 25HP 2 stroke is too heavy. I went back to an older Evinrude 25 from the mid 80's.
The same boat moves along at about 21 mph with just me in it when I run my 1980's Johnson 15 HP too.
I would say that the boat is ok with the 15hp, but far more fun and usable with the 25 hp on it, especially with more than one person.

I've also had a few 14' boats with very shallow sides, those were only rated at 15 or 20 hp max.

Tacklewasher · Oct 15, 2009

Re: 15hp on a 14' Alum too heavy?

My 14' Harbercraft is rated for 20.

I like the idea of an 80's Johhny/Rude 15 as it is the same weight as the 9.9.

I've only had my boat out twice (just bought it) and only had a 46lb electric on it. One day I will drop my 10hp Honda 4 stroke and see how it does, but it is usually bolted to my other boat as a kicker.

Jeep Man · Oct 15, 2009

Re: 15hp on a 14' Alum too heavy?

I have a 1955 pre-Mirrocraft and it's rated for a 25 hp. This winter, I'll be adding the same to mine....live well, floor, storage, etc. Weight aside, you may need the extra horses to push the additional weight. I'd keep an eye for a 20 or 25.

RandyEvers · May 12, 2011

Re: 15hp on a 14' Alum too heavy?

I have a 14' aluminum Valco (1971) with an electric start 1973 Mercury 200 (20H.P.). The front of the boat from middle seat to bow is built up with a heavy 5/8" plywood, flat fishing deck/chair, etc. and there is a MinnKota elect. trolling motor on the bow. With this weight and one 220lb person in it, I get 29 mph (gps) at full throttle and the boat handles just great. However, without the additional weight, I am guessing the 20 hp might be pushing the limits.

However, I have the original 1973 owners manual for the Merc and the spec tables in the book shows that with boats of 12' to 15' the Merc 200, with 2-blade, 11 pitch prop should develop 4800-5200 RPM, producing 28-33 mph.

But I can definitely say that from the description of your boat, a 15 h.p. is definititely not too much motor.

NYGiants · May 12, 2011

Re: 15hp on a 14' Alum too heavy?

I have a 03 25hp Johnson 2stroke on my Lund weighs 450lbs dry. Rated up to 40hp runs 25mph with 2 people 20mph 3 people

Home Cookin' · May 12, 2011

Re: 15hp on a 14' Alum too heavy?

old thread; timeless topic since the 14' boat is so popular.

An important factor to keep in mind is that you can safely put a lot more horses on a boat with a console than without. For a 14' tiller I found a 25 to be OK for experienced adults but too much for the children who were using it; 15 is better. I would not go over 25/tiller for anyone. Console up to about 35.

BF · May 12, 2011

Re: 15hp on a 14' Alum too heavy?

Early 80's Johnson/Evinrude 15 hp would be hard to beat. I have an '82 and I don't think anything can touch them for power to size/weight. I think they're ~80 lbs. 15 HP in a 9.9 sized package. They are fantastic slow trollers and quiet at idle. Very early ones (70's) had point ignition, by the 80's it was electronic. I like that they are light enough that it's not a hassle to pull it off and stick it in the garage/shed for the winter or between uses. I also have a 25 hp Merc EFI 4 stroke... it's heavy and is a bit too fast for slow trolling. I like fishing with the 15 hp better. With a nearly empty boat, the 15 almost keeps up to a similar boat with the 25 hp on it. Add some weight and the 25 shines.

*** dang... got suckered in to replying to an old thread... started in 09 ***

15hp on a 14' Alum too heavy?

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