Trolling Motor power loss

[buc]

I replaced my trolling motor battery this year in Jan/Feb but I don't get the power out of the trolling motor that I did from my old battery, I replace the old battery because the same thing was happening loss of power even at full charge. If I bump up to 5 is like 3 use to be, and drops quick, yesterday at Lake Acworth ( I had to try after Mike's post) We fished for about 4 hours most of the time on 1/2/setting and on the way back in barely made it back in #5 barely moving. The trolling motor is only 5 years old it's a MinKoda 40lb bow mounted hand controlled, the battery is only afew months old from Walmart. Two years ago at #5 would move me along at a pretty good clip, I don't have a large heavy boat, 16' johnboat trolling motor on the front, depth finder, 25 hp Yamaha tiller steering on the back.
It's a good boat for us but the trolling motor is driving me nuts, any thoughts would be appreciated.

[leapnlineman]

Take your prop off and check for any fishing line wrapped around the shaft. Were both old and new batteries the same Amperage?

[5 BASS LIMIT]

Load test the battery first before you do anything.