is it to heavy

mike stam

Recruit
Joined
Jan 23, 2022
Messages
1
just retired my old jhonson 25 and want to put on a 15 hp yamaha 4stroke. the boat is a 1986 valco 14' bass boat conversion. boat is rated for max 25hp,712lbs ?
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Welcome to IBoats,

You won't like a 15 after boating with a 25 HP motor, invest wise go tad higher to at least a 20 HP...

Happy Boating
 

RMClark

Petty Officer 3rd Class
Joined
Jul 19, 2020
Messages
94
A 15HP motor isn't too heavy for your boat. If you're buying new, the makers in that class have done a lot to reduce weight of those motors.

Can't advise on the performance aspect of what you want on your boat. It will depend on your use habits and what you are accustomed to.

My 14 foot Lund had a 30HP Johnson on it when I bought it. I replaced it because it was giving me trouble and was not electric start. I hung a new 20HP Merc on the back, and the setup is fine for the smaller and medium size lakes that I fish in this area. Many of those lakes are limited to "no wake" speeds, so a lesser HP setup is good for me. Still, that 20HP Merc can push the boat at 22-23 mph with two fisherman and gear.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,666
You won't be happy with it.........you may think you will but you won't.......spend the money, get the 25 back on there. The money will be gone but the performance will be with you every time you turn the key to START. You'll pat yourself on the back for being so wise..........
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Yep, as per Texasmark spot on recommendation, install a 25 HP motor on that transom, to achieve top boat/motor water performance go for a prop maximization...

Happy Boating
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
My thought is you may not need the performance of a 25 for what it is you're asking the boat to do.

We all know boats are an exercise in compromises. Maybe the 4 stroke virtues outweigh any performance losses.

So I'll answer the OP's question regarding weight. No, I think you'd be fine with the weight of that 15.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
A 14 footer bass boat with just a underpowered 15 HP motor for me not even in dreams or if was given for free. The OP has not stated his precise boating requirements such as : fooling around, fishing, cruising on lakes, rivers, open water, pulling water toys, number of regular passengers which is key to know well in advance for a correct no repent HP motor selection.

Such scenarios will make all the difference with whichever HP motor is finally chosen. Regardles of the added weight which can be compensated with a much better deck load distribution, it's better to count with more power not needing it than less when,.. you already know the saying behind it. LOL!!

Happy Boating
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,163
With a family of 4 we ran a 14' tinny rated for 25 HP with a widdle 9.5 'Rude. We had more fun and good times with that boat than the guy down the street with a Donzi equipped with twin 454's.

I also do fine at 65 mph on the interstate when others are bored unless they do 90.

Its all about what you want to do. Do you want to go boating and have a family affair, or do you NEED to be the fastest boat on the lake?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,666
My thought is you may not need the performance of a 25 for what it is you're asking the boat to do.

We all know boats are an exercise in compromises. Maybe the 4 stroke virtues outweigh any performance losses.

So I'll answer the OP's question regarding weight. No, I think you'd be fine with the weight of that 15.
I'll iterate.....get the 25 HP!
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
With a family of 4 we ran a 14' tinny rated for 25 HP with a widdle 9.5 'Rude. Its all about what you want to do.
It's all related about what you want to do and where you want to do it. OTOH, It's not the same boating with a 14 tinny with an underpowered motor for family oriented purposes compared to same tinny powered with a larger 20-25 HP motor and 4 grown ups. Fast displacement speed is extremely boring, plane speed is all. If it's not a budget issue go for a 20-25 HP motor eyes closed...

Happy Boating
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,818
Gave the grandson a 12' aluminum.----Powered with a 1963 10 hp Johnson.-----We were surrounded by folks with $100,000 boats , perhaps with monthly payments.-----But we had a lot of fun.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Gave the grandson a 12' aluminum.----Powered with a 1963 10 hp Johnson.-----We were surrounded by folks with $100,000 boats , perhaps with monthly payments.-----But we had a lot of fun.
It's all about defining what Fun is for each individual with whichever boat/motor combo he's boating with. Don't need extremely costly combos to have fun with along associated free bragging with them. Almost anything that floats powered with a motor will suffice to have Fun....

Happy Boating
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,163
Fast displacement speed is extremely boring, plane speed is all.

Our 14' tinny with a 9.5 will plane with 2 fat adults and 2 skinny pre-teens aboard.

Of course, that was after prop optimization, induction tach and data collection.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,163
What about before with same load without previously doing nothing ?

Happy Boating​
Acceptable, but not optimum. The guy I bought the boat from was an old codger that had been in the bizness since 1945. He knew his stuff, and set up the boat pretty darn good, unlike the computer geeks running the shops today.

In later years I upgraded to the max spec of 25HP, and the boat was squirrely and ran like crap. Found out that 18HP was optimum. Nevertheless, put the old 9.5 back on and she does everything I ever wanted and more.

If I want speed and excitement, we take out our 10' long 'ski equipped with 185 HP.
 
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