So where should I start?? The grounding strap on outdrive is broke. After I fix that where do you guys suggest looking. There are only a million wires on a boat

Trolling motors batteries are not hooked up to cranking batteries. I took all batteries out when got the boat and cleaned the bilge.

Make sure trolling motor and cranking motor share the same ground.


That electrolysis could be coming from another boat parked nearby also.

You haven't finished looking. The connection can be anywhere the two Grounds can be connected, not just at the batteries in the rear equipment compartment. You've indicated you have looked in one place; there are others.

Someone who didn't know what they were doing may have connected a boat battery Ground wire at the bow to the TM in some way (putting a bonding wire under a bolt or nut, for instance).

Sometimes people attach a Ground wire from a graph at the bow to the frame of a TM mount, believing this will decrease interference. That's pointless and as GS stated, a very bad move. You'll need to do a close inspection at the bow to truly determine if the two Grounds have been connected. This could be hidden from view, such as inside the bow wiring access port, on the back of the TM receptacle, etc.

That is probably where your problem is. Drop those back off and go the other route. Also purchase the newest and greatest trolling motor plug you can get. There is a flat ground plate inside that can go bad but still give connection. You will be able to see it through the clear plastic. Make sure all the wires inside this new plug are as tight as possible on all the screw post connections and under each screw as neat as possible.

Make sure trolling motor and cranking motor share the same ground.


That electrolysis could be coming from another boat parked nearby also.