Is bigger always better?

[Homer J]

On a light 17ft open boat (dory type) with a Max rating of 115hp is this really the best bet?

Would 90hp be sufficient (pooling around, waterskiing, donuts, fishing), lighter so easier to put on a trailer, more fuel efficient, cheaper insurance.

I have a 16yr old son who tells me I need to put the max power on or I’ll regret it later (he would wouldn’t he?)

Which one of us is right? There isn’t a great deal of cost difference between the two about 10% or £800.

 

[jrudge]

For £800 I would buy the bigger one.

More power to get on the plane, deal with fouling etc.

 

[[2068]]

Mercury / Mariner 90hp and 115hp are the same blocks in different states of tune.
So, no weight difference.
The extra £800 will give you a few extra knots flat out - only you can decide if it’s worth it.
Fuel consumption at the same speed will be about the same - 115hp just gives you the option to burn more if you want to.

 

[BruceK]

I have a 16yr old son who tells me I need to put the max power on or I’ll regret it later (he would wouldn’t he?)

And so he should, bright lad that one. Must get it from his mum

 

[Bouba]

We can all tell you how much you will miss the 25hp. But only you can tell us how much you will miss the £800

 

[swatkins]

Always get the biggest one you can afford there is no going back. For £800 its there if you need it. To upgrade later will be really expensive - new engine

 

[QBhoy]

Perhaps not an issue here...but if this might be an older boat you have that has a rated HP of 115...it will be for a 2 stroke.
If the new considered engine is a 4 stroke and older than 2015/16 then it will be likely another 1/3rd the weight of the original engine they referred to when rated new.
Just a thought. If it’s not applicable. Fair play.
Otherwise then go for the biggest you can. Bigger doesn’t always mean more fuel.
To answer your other question...a 90 will be just fine for the odd hoon about and water ski. More than fine.