10ft JonBoat Motor?

I wouldn't want to put anything on it except electric.  I had a 10 footer not alot of freeboard, have to keep the movement to a minium.  Weight of gas motor, tank, plus you is going to decrease the freeboard especially if it's moving at  a good clip.  A nice electric 30 or 40 lb. thrust would move the boat.  Chcek your capacity plate to see what horse power the boat is rated for.

First, You must look to see what the boats capacity plate says you can have for max hp, and capacitys of weight.
Thats the LAW to have one. That will narrow down your motor options real fast

I understand what SPG is saying with the electric, how ever i do not agree with his reasons. Here is why, the motor that i believe you would be allowed to run on your boat (capacity plate max hp rating) would be 5hp max (thats a guess) Many 5hp outboards and smaller have intergrated fuel tanks with the motors, my 4hp motor is like that. Also my 4hp will push my heavy 14foot boat at 6mph (it is used for a kicker)

With fuel my 4hp weights around 40lbs.
Look at the weight of a battery, around 46lbs for a small group size 24 battery. Now also add in the 10lbs or so for the electric motor itself, your closer to 60lbs for that motor rig. Also you have to contend with the lost space that battery takes up in your boat.

I did not say all of that to discurage you electric motor, i think they are wonderful. I wanted to bring in to perspective that most small outboats will weigh less than electric.

If you will be doing alot of small lake fishing, or staying fairly close to the launch area and speed is not an issue, electic might be a better option. They are quiter, and always turn on. With gas you have to start them to move, sometime a hassle, but you will move faster than electric. It is a toss up only you can make the decision