When I bought my boat there was an inline fuse on the trolling motor battery.  I have a 37lb thrust Motorguide TM with a 12v battery.  Does anyone have any idea what size fuse I should be using in this?  My cousin has a much newer Motorguide TM and in the manual it says to use a 50 amp.  I want to try and avoid putting in a fuse with to high of a break point for obvious reasons.  

Thanks guys.

Sorry, I can't help with the amperage, but you should consider replacing the fuse with a breaker switch.  Sucks to be out on the water and blow a fuse.

Could I get a breaker at any hardware store or is this something I would have to get at basspro, cabelas, or online?

I would say probably not unless they had a marine dept.  If you have a marine store like West marine or Boaters World you can find it there.  Probably find one at a boat dealer too.  

Shortbasser

Try to contact a motorguide dealer in your area and ask them.  It is probably going to be a 40 or 50 amp.  A dealer will also sell the breakers.  I have a manual reset small gray shortstop 50 amp on mine and it was around ten dollars.  

Pounds of thrust dont apply much here. The fact that they all use a 12 volt  D. C. battery is what warrants the use of a 50 amp fuse or breaker which is more intended to protect the wiring first before it protects the motor.

Pounds of thrust dont apply much here. The fact that they all use a 12 volt D. C. battery is what warrants the use of a 50 amp fuse or breaker which is more intended to protect the wiring first before it protects the motor.

Really?? I always thought you could use the assumption that for every pound thrust,it draws about 1 amp?

I doubt a 30lbs TM draws as many amps as a 55lbs TM at full throttle.I might be wrong though.

Check around but I think a 40amp braker should do you fine.

I will try and call a motor guide dealer tomorrow.  Thanks for the input.