trolling getting weak?

I have a pro 4300 MG on a 17.5 ft alum fisher' this should be plenty of motor on this boat on a fairly calm day, it just seem's like it lack's power. How often should you change the brushes in these motor's and will it help the thrust any. On a windy day it has to be in 5 (highest setting) to make any head way. Batteries are good, hold a good charge and last all day. I'm looking at new Minn kota maxium 70 but I've had to dump to $$ in my truck lately and it will be a little while for new a TM.
Thanks Kydog
sorry about thread title, should have trolling motor getting weak, can't edit title!

Have you checked the cables and the connections? Do the cables heat up while you are trolling? Bad connections can alter the speed that you troll.

Hope this helps and good luck,

David

Batteries could still be weak.. How old are they?
Even if your trolling motor feels week, it may not be worth the rebuild cost to try to get a couple pounds of thrust out of it.
I upgraded mine with a used unit last year and then that used unit needed rebuilt. I put all new controls/brushes in the lower section and cleaned it out well. overall. I couldn't tell a whole lot of difference from before it quit.
I could tell a little bit of difference when I upgraded my batteries.

one battery is a year old and the other is 2 yrs old, they are kept on a on a onboard charger. Maybe the 43 lbs of thrust are not enough.
kydog

check to see if some fishing line has gotten around the shaft, it can pick up line even if it is not yours, that would slow it down, and could cut into your seal, I take my prop off every year just check. hope it helps

Gary

43 lbs of thrust isn't much. my 55mk dosn't pull very well either.

[QUOTE=kygorski;404376]43 lbs of thrust isn't much. my 55mk dosn't pull very well either.[/QUOTE]
It might be time to upgrade to 24v 70 lber, more power!!!!!!!!!!

if it had plenty of power before then it is prob battery or line wrapped up in the prop like stated above.

[QUOTE=greenriverman1;404340]Have you checked the cables and the connections? Do the cables heat up while you are trolling? Bad connections can alter the speed that you troll.

Hope this helps and good luck,

David[/QUOTE]

Ditto on the cables and wires. I have helped two buddies with similar problems and we rewired the TM. Upgrading to a larger wire size on older TM's makes a big difference in performance. Also check the wires from the batteries to the TM plug. Go as larger here as well, around a 4-6 guage works best in my experience. Good luck.

Joe