Im having a really hard time making a decision. I have a 16ft mirrocraft, I plan on putting a floor in it and a bow mounted trolling motor on the front, plus batteries. Thats a lot of weight. Right now I have a '82 Mercury 25hp, but it seems like it will be too small. I have the option to get a '74 50hp Mercury, but I dont know if my boat can hold it.

Either way I am going to have to build a transom for my boat, it has the dipped down lower transom and I need it to be higher up for my long shaft motor. But can I make a transom that will hold the 50?

Both motors at in great shape and great running order, the 25 is tiller the 50 has controls.

Thanks,

Christian

Do you know what the maximum size motor allowed on the boat is? 

No its old and doesn't have the little plate that tells you that. But im going to have to build a raised up reinforced transom either way.

You have to remember, horsepower wise, that 50 is only about a 42 by today's rating method. The big difference is going to be the weight. Depending on the gauge aluminum, if it's a heavy gauge, the hp is not going to be a problem. I ran a 50 Johnson on a 15ft console type Jon for years.

A 16 foot boat designed for a tiller motor that came with bench seats is only rated for a 25hp motor no matter what you do to the transom. Putting a 50 on that would be very dangerous and probably against the law. 

I have a 1650 xpress all welded thats rated for a 40hp. That being said when I first purchased the boat I put a 30hp four stroke on it and it worked fine. Last year I wanted more power and speed so I was stuck between a 40hp or a 50hp. The only reason was the 40 and 50 weighed exactly the same but In the end I ended up puttin a 50hp Tohatsu two smoke on there and I am so glad I did. Top end is right at 40mph and I never have to trim the motor down to get on plane no matter what load I am carrying. Would not have done it any other way.