I have a pontoon boat with a 50 HP Mercury motor on it and am thinking about replacing it with a 115 HP Mercur?

Mercury motor. Is there going to be a problem since the boat is only rated for a 90 HP. Is the weight difference between a 115 and a 90 significant?I have a pontoon boat with a 50 HP Mercury motor on it and am thinking about replacing it with a 115 HP Mercur?
1. Chances are that going up one notch in motor size above your rating will be OK. This is especially true if you live at altitude like Colorado. It is commonplace to get the next size up engine above the rating to make up for the power loss at elevation. 2. Previous suggestion of adding 3/4 plywood to your transom a good one and not too complicated to do 3. Be really careful driving at higher speeds especially during choppy water until you see if your pontoons will need addittional "lift" at the noses.I have a pontoon boat with a 50 HP Mercury motor on it and am thinking about replacing it with a 115 HP Mercur?
Hi,

It all depends on how many cylinder the engines are. If they are both the old straight 6 cylinder engines then they weigh the same anyway.

You can always screw a square peice of 3/4" ply onto the back of your transom (level with the top) before fitting the engine if you have any doubts, as this will add extra stength to your transom and spread the load. I usually cut the ply so that it sticks out between 3 and 4 inches either side of the engine saddle and a couple of inches at the bottom.

Hope this helps, Mark.I have a pontoon boat with a 50 HP Mercury motor on it and am thinking about replacing it with a 115 HP Mercur?
The power and performance is significant.

The rating is based on the transom's capability.

If you put too much on a boat that is not made for it,

you might damage to structure.

Stay within the manufacturer's specs.