My Ultrex 80#, 24V won't run at any higher speed than 6 when the prop is in the water...when I pull the prop out of the water it'll run on 10. I've checked all the connections at the batteries, the 60A breaker isn't tripping, and I've got 28V at the plug. When it stops, the foot pedal will flash and beep like when I flip the switch on at the beginning of the day. Running on 6 or lower presents no problems. Any ideas?

I have a very similar issue. Same TM. Mine will run on 7 all day. 8 for around 20 minutes. 9 for about 1 minute. Full speed for around 10-15 seconds. It shuts off and “reboots” for lack of a better word.

I have bought new batteries, removed all the circuit breakers , added a newer set of breakers. Checked for really clean, solid connections throughout the power paths.

Just figure it’s a problem I’ll live with till I get a new boat this summer.

What gauge wire is ran between your batteries and TM? It may not be heavy enough to carry the load the batteries are trying to push.

Mine is 6 gauge. It started doing this after the shaft and motor assembly was replaced under warranty.

That's weird. Never had that issue with mine. I can run it on 10 for hours. I'd get it to a MK service center to get it checked out.

Mine is 6 AWG...it only started happening after the cable from the foot pedal to the 60A breaker came loose...I reattached it and now I can't even pull it apart. Like Steez, I also got new batteries and checked for clean connections everywhere...the only thing I haven't done yet is change out the breaker.

Look for a voltage drop at the trolling motor. Sounds like a dodgy connection somewhere that is not showing itself until you put it under high load. Did the wire pull itself out of the lug at the breaker? When you repaired the connection at the breaker, what did you do? If the 6ga was straight copper and was tarnished or corroded and you crimped a new lug on it or reused the old lug, it could be causing some resistance at that connection. It will work fine at low load, but once you place more demand on it, it will fail. If that is the case, pull the wire out of the lug or cut the lug off, strip the wire back to new shiny copper, and crimp a new lug on. If you need help and your near DFW, I have a 6ga - 1/0ga lug crimping tool and I think I still have some 6ga lugs somewhere from installing my Ultrex.

^^^ Mark is on the money on this. I too would like to hear how you "repaired" that pulled out wire. Tell us about the "reattach" process. Unless you have knowledge in things electrical, it may be lacking. Hint: squeezing a crimp with standard pliers is NOT a "repair" - that doesn't work. When you get above 10 gauge, a specialty tool that most don't have is needed.

I'm curious; where is your breaker, and how did the wire manage to "come loose", and at which end? We probably need to see photos of each end of the cable in question.

Sounds like a breaker or corrosion or both