motor size to boat size

[superdave1984]

I am looking at getting a used outboard for my 12' jon boat. Currently it has a 5 hp B&S on it. (It was cheap and it ran although my trolling motor moves the boat faster.) I am looking at a 25 HP Mariner , a 40 HP Merc, and also a Force 4, all are about the same price used and in about the same shape with the possible exception of the merc which looks like it has considerably more hours on it. I can't recall the size of the Force, but it is similar to the Mariner. Any preferences? They are pull start/tiller steer models. I know size and speed are important, but how big is too big on a boat that size? I am thinking the Mariner is probably as big as I want, but I think the Force is a 4-stroke which I like.

[crash]

I can't tell you the size for the boat you have, but all you have mentioned sound like more motor than I'd be willing to put on it. You might try going to some boat maker sites and finding a compariable boat (length, width, and side height) and see what they have listed as the max hp.

[Carl Palmer]

You may want to look at the I.D. plate for capacities and H.P. I guarantee ya the 40 horse will hurt you bad if your're not careful. Not saying you can't handle it--just saying wow! Probably won't be much worse then skipping a stone on the water.

[superdave1984]

Yeah, I think the 40 is way too much. Might buy it because of the price and resell it later or keep it in case I get a bigger boat.

[ykkapslabhunter]

I agree, most 12 ft jon boats I've ever saw are only rated for 15hp max unless they are all-welded then put whatever you want on there and hold on!

[freeflow_23]

I know my old 12' job boat would have sank with a 25 on the back. Definitely try to find the I.D. plate for max HP and weight info.
I had a Briggs 5hp on my old boat too. I imagine the new owner is still "mowing the lake". :D

[Barnacle Bill]

Definitely check the plate. It will tell you the max hp you can put on it. More goes into that than just the length. For instance, I have a 16 ft boat with a 150 on it. More motor than I need but it is rated for it.

[Eager Beaver]

I would think that a 9.9 hp or 15 hp at max for this boat. any more than that and it would walk thru the transom.

[sac-a-lait]

if you put too much power on it and happen to be running fast and have to turn quickly....HANG ONE...Cause someone's going out of the boat

[shadow]

with the others on here that a 40HP is too much for a 12 foot boat. I would also stay away from any Force engines. If I rember right right a Force is just a cheap Mercury. Don't get me wrong I love Mercurys but I wouldn't own a Force. Had a friend who had one once and he had nothing but problems with it.
As far as how big of a motor, I wouldn't go any bigger than a 25 with a 12 foot boat, but like someone said, it is probably only rated for a 15 HP.
Dwyane