I have a 14' wood boat (like a jon boat) that I power with a 2.5 hp gas motor and it does very well getting from point a to point b. However, I want to add a trolling motor so I can maneuver around some areas without spoiling the fish. I'd guess the boat weighs maybe 1000 pounds fully loaded with me in it. I am look at a Minn Kota Endura (c2 or max, haven't decided yet).

I was looking at a 40lb thrust or 55 lb thrust. Both are 12v of course. The price difference is like $60 so who cares. I just didn't know if there was a downside to getting the bigger one and running it on lower speed.

Also, do you think one good deep cycle marine battery is enough? I want to be able to stay out all day and will be running a small fish finder. I would be using the gas motor to do longer distance driving.

Thanks for your input.

One battery will be more than enough for either trolling motor. Bigger is better unless you are trying to keep the weight down. I say this from experience, you will be just fine on the lower settings and it will run all day like that. When there is a little wind, it's great to be able to hold that little boat where you want it with that trolling motor. It's also fun to throw a wake with it while chasing schooling sand bass.

Put a solar battery tender on the battery.

I don't think you can have too powerful of a trolling motor. The more powerful the motor, the less it works to move your boat. So your battery will last longer if you have a bigger. Like mud shark said, "bigger is better unless you are trying to keep the weight down."

run the small fish finder on a separate small 12v battery, like the kind you put in a solar gate.

You might be surprised that there isn't that much difference between a 40 and a 55. I know I was. With that being said, I would go 55.

No such thing as too much trolling motor. I had a MK101 36v in my old 17' stratos. It would pull that boat around at 4.5 mph.

Get the bigger one. The only time that I have seen a trolling motor too big for the boat is when you have IPilot or Pinpoint. Too much motor on a small boat will make it wander more. I first noticed this when a friend of mine put a 112lb Terrova on a 14' aluminum boat for both primary power and trolling motor power. When it went to correct for position, it would sling that boat around like a rag doll and go too far past and then do it again in the wrong direction. It will dump your on your butt if you are not ready.