Is a 1500 mercury going to be to big for a 15ft fiberglass?

pleasehelp

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May 7, 2014
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I have a macho 15ft fiberglass ski boat. It's running a 60 go Johnson 2 stroke at the moment but seams to struggle to get up onto the plain when towing a tube plus people in the boat. Don't know if a 150 mercury is going to be to much or not for a small boat?
 

hockynut2

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Jul 12, 2013
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Re: Is a 1500 mercury going to be to big for a 15ft fiberglass?

Not 100% sure but guessing the 150 is way more than you will need. I see a lot of 15ft with 90-115hp motors that seem to do the trick. Check and see if your hull has a info plate on it usually it will say max hp that you can use.
 

skibrain

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Jun 17, 2004
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Re: Is a 1500 mercury going to be to big for a 15ft fiberglass?

60 hp is boderline for holeshot, but chrck to see prop pitch. dropping from 17 to 15" would increase hole shot with the motor you have.

Agree check HP for max rating on coast guard plate. If you are lookinf at older motors, with Johnson/Evinrude, the 85 hp through 115 or even 135 hp in some years share the same displacement V4. Merc 6cyl 90-150 hp of that era shared same. The "newer" (20 yr old) 150 merc is a larger still V6 and def. too big. As long as you aren't over-powered, more displacement and keeping a lower pitch prop will help with power.
 

AndyHUK

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Jun 25, 2014
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Yup, a 150 will be too big, you will need a hell of an offset to allow for torque steer. Max i would go would be 115-120
 

Frank Acampora

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Jan 19, 2007
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Unless the hull is a specialty racing model rated for that horsepower, you will be illegal in most states. Will the engine be physically too big? maybe, maybe not. In the past I have had a 14 foot flat bottom upon which I hung a 125 and did 60. I do have a 5 cylinder Force 150 which I will use on it when I get the engine together.

You do need to be careful though: There does come a point where weight and horsepower DOES become too much for the hull and handling is adversely affected. The hull will become dangerous at speed.

Of course, you must also remember that you simply can not hang the engine on the transom and expect to go fast. You MUST logically look at the hull and reinforce not only the transom but other parts of the hull to handle the extra stresses of the engine and speed--otherwise you will find that you, the hull, and the engine become "swimmers." Yes, I have had different overpowered hulls upside-down a couple of times. It happens fast and I was lucky. No one says that you will be lucky too!

Back to the 14 footer with the 125: I reinforced the transom and deck, rebuilt the stringers and floor, added extra cross braces to the floor, built very rugged seat mounts, and glued the cap and hull together. Even then, I spent about an hour running at 60 then went home and spent several hours re-gluing the hull.

Now, I can't recommend that you actually overpower your hull--the other members of the forum would have a fit--but the decision is ultimately yours. Just be aware that without proper thought and equipment you are getting into a dangerous situation, both to yourself and to other boaters in the vicinity. You know that if you put an engine that big on your hull, you have no intention of trolling with it. We all know what position the control handle will live in.
 
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Oct 22, 2007
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My guess (and it's nothing more than a guess - you really need to determine what your boat is rated for) is that a 90 would be what you want to get. I had a 15 ft boat with a 90 (which happened to be what it was rated for) that worked perfectly for pulling skiers. A 150 on that size boat seems very excessive.
 
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