Trolling motor battery / power question

I have a MK Endura C2 / 45 lb thrust on the back of my 14 footer. Lately I’ve noticed the motor doesn’t really push much unless turned on the highest setting. Just drifting downstream last night was about 3mph. Speeds 1 through 3 seemed to do almost nothing. Bumping to speed 4 gave me only + .3 or maybe .5mph, and then speed 5 would add a whole 1.5 to 1.7mph. It made it tricky to find the sweet spot. 5 was a little too fast, 4 wasn’t enough.

I know this is a cheap TM and I’d see an improvement if I stepped up to an Endura Max or something else with variable speed, but I used to be able to at least see a more gradual increase in speed as I shifted up.

Does this sound like an issue with the TM, or with the battery? It’s a group 31 deep cycle in its 3rd year of regular use. The TM is the only thing powered by this battery.

Thanks!

Try another 12v battery – any battery. If the problem persists, it’s the TM.
I have two MinnKotas – both 55# thrust (one is a short shaft). Had the same problem, took them apart and changed parts suggested by MK’s tech support. Works like new and every speed is what it’s supposed to be.

Have you cleaned the battery terminals? Sounds like high resistance somewhere between the battery and the motor. At lower speed settings, high resistance has a greater effect. If it’s not at the terminals, it’s somewhere inside the head or at the motor itself.

Take off the prop and check for debris inside the housing. I recently took the prop of my TM and found some fishing line, weeds, and other debris wrapped in there.

Thanks all for the thoughts.

– Short of pulling my car battery or using a tiny vexilar battery, I don’t have access to another 12v to test. (Pull start only on my boat.) But I’ll see what I can dig up.

– Ron — battery terminals are clean as a whistle but you did get me thinking about resistance and capacitance. I have the battery up in the bow for better weight distribution, which required an extension to the power cable all the way back to the stern. I used the same heavy wire gauge (pulled from a fried MK motor) but I should go back and check the splices. Never been an issue ’til this past month but it’s possible something went bad.

– Gimruis — I’ll check that out as well.

Thanks all.