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Switching Source for Trolling Motor

R

randomguy

New member
Hey folks,

I live in a subdivision with two lakes. One of the lakes is electric trolling motor only. So we have been out cruising before and then found ourselves with a dead battery, so I had to move the trolling motor connections over to my crank battery for my gas engine. I looked into getting a on off on switch so that I could just throw a switch instead of having to break all the connections if this ever happened again. I got a switch and rigged this up two seasons ago. It worked great. Now for some reason this season when I have this system hooked up, the engine will not start. I have taken the switch out and tested it with a meter and it functions exactly as it should. The system worked great for two seasons, and now will not work. What am I missing? I thought that for some reason the engine might not light like the two grounds of the batteries being connected. So I disconnected the two hot wires and just had the two grounds of the two batteries connected to test and the the engine starts just fine. But when I have the hots connected, regardless of what position the switch is in, even off, the engine will not start. Thoughts on this?

Thanks

IMG_0550.jpeg
 
Your diagram is not complete...or is inaccurate.

"...will not start." means won't crank over or cranks over but will not run?

As a rule, a DVM isn't much value in testing a high current device when its removed from the circuit...

Without the missing details, my best guess is that the 'no start' issue is independent of the trolling motor selector modification...
 
Thanks for getting back. When I turn the key, I get a click from the engine but it doesn’t turn over. When
I remove the cables running from the hot terminals to the switch, it starts like gangbusters.

What I don’t understand is that the selector tests as an open when it’s supposed to. So in my mind, I don’t follow how the engine even knows that it’s there.

what about the sketch seems to be incomplete or inaccurate?
 
Your diagram shows a crank battery that's connected to a house circuit but doesn't show the gasoline engine connected anywhere...

only getting a click when the engine key is turned to the START position suggests a bad connection somewhere in its starting circuit...
 
makomark said:
Your diagram shows a crank battery that's connected to a house circuit but doesn't show the gasoline engine connected anywhere...

only getting a click when the engine key is turned to the START position suggests a bad connection somewhere in its starting circuit...
Click to expand...
Fair point. Gas engine is connected directly to the crank battery traditionally. Red to +, black to -

Regarding the click, yes this makes sense. But when I isolate the connections to the selector switch and change only one variable by removing them, I get the desired result. Going back to something you said above, do you think that the switch could be passing a bench test, but then not functioning properly in the circuit?

IMG_0551.jpeg
 
your words suggest you are changing more than one variable at a time...

I'd say if you leave the 'trolling motor source selector switch (6008)' wired up, you should be able to isolate that from the engine wiring by just removing the 30amp fuse in the line between the cranking battery and the 6008 switch....if this isn't the case, then your boat's wiring doesn't reflect whats in the modified drawing...
 
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