trolling motor cuts out under load

Mopar1

Recruit
Joined
Aug 16, 2016
Messages
4
Hey guys. I have a duramax drifter 3 trolling motor that cuts to about half speed when I put it in the water. It seems to work fine when its out of the water. Also when it cuts to half speed and I turn the boat it cuts out completely. If I turn the throttle to 0 and crank it to full it goes full throttle but right away cuts to half or less speed. I charged the battery just before I used it and it's hardly been used. Any help would be greatly appreciated.
 

fishrdan

Admiral
Joined
Jan 25, 2008
Messages
6,989
Duramax Drifter 3? Never heard of it, what voltage and # thrust is it? Is the TM connected direct to the battery or through a wire run (what size of wire?). How old is the battery, what size and how often do you charge it? Charge after each use and then every couple of months, or let it sit for months on end and go dead in the off season?

Slap a volt meter on the battery and while in the water, turn the TM on high. On a (good) fresh charged battery it should hold around 12.6 - 12.5, touch of voltage drop, but certainly not down to around 12V or lower. Check the voltage at the end of the wire run, if using a wire run.

Check all wire connections to make sure they are clean and tight. I have filled a garbage can at home for testing like this, just make sure the TM is locked in position so it doesn't turn and tear things up. Not a great test as the TM will suck air, but it will load the prop to some extent.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
First of all Mopar1, :welcome: to iboat. Nice to have you aboard...

The thing that stand out to me is the fact that you stated you just changed the battery. And since your trolling motor starts out okay and then change to "half speed" points to something heating up fast and reducing the current capability. And that something points to the battery connections to me. Did you clean those connection to bright shiny clean metal before connecting them up? If not, try that first and see what happens after you make certain you really tighten them down good. JMHO
 

Mopar1

Recruit
Joined
Aug 16, 2016
Messages
4
First of all Mopar1, :welcome: to iboat. Nice to have you aboard...

The thing that stand out to me is the fact that you stated you just changed the battery. And since your trolling motor starts out okay and then change to "half speed" points to something heating up fast and reducing the current capability. And that something points to the battery connections to me. Did you clean those connection to bright shiny clean metal before connecting them up? If not, try that first and see what happens after you make certain you really tighten them down good. JMHO
I cleaned them good, that's the first thing I thought would be a problem
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I cleaned them good, that's the first thing I thought would be a problem

Well it might be time yo break out the DVM now. If you have such a meter, attach it to the trolling motor positive and negative wires and test the motor in a trash can in the yard if you can. See what happens to the voltage when you run it. If that voltage stays pretty much level, then attach the meter to the wires going to the actual foot of the TM and see what that voltage reads. If that voltage drops, your problem is in the TM head unit. I would check any and all switches in the head unit. Could be one of them is got some burnt contacts. :noidea:
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Two things point to bad/weak battery. 1). You said you charged it BEFORE you use. The question therefore is how long the battery sat in partially discharged state? You always charge immediately AFTER use. 2). You can wonder about this but you cannot reach a conclusion unless you test battery voltage under load. Just do it!
 
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