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ProjectPro · 09-13-2020, 02:09 PM

It started as a no-start problem. The engine would start right up if the battery was completely charged, but not if it was even slightly discharged.

My trusted mechanic (who drives a Monaco DP) diagnosed the problem as a bad cable to the starter. He didn't want to disassemble the panel above the batteries to find the problem, so he just ran a cable directly from the battery to the starter. While that fixed the starting problem, it caused a new one. The chassis disconnect switch no longer does anything. I found the schematic, and power to the starting battery goes through the chassis disconnect switch, much to my mechanic's surprise. So the new cable feeds power to the starter via the new cable, then power goes to the load side of the disconnect switch via the old cable.

My mechanic said he hasn't seen a switched starter cable before - that all he's seen have a cable directly from the battery to the starter, which won't drain any juice unless the key is turned.

I( suspect that the root cause of the original problem is a bad battery disconnect switch. I could stop the battery draining by disconnecting the original cable at the starter (and insulating it super well to prevent shorting and possible fire), but that would leave me with a failing disconnect switch. At the small current loads that go through the switch with the starter not going through it, it will probably work OK at least for a while. So my questions:

1) Any problem with wiring the starter directly to the battery?

2) Should I replace the disconnect switch (if so, I'll splurge for a Guest marine unit)

3) Is a lot of disassembly involved with changing out the cutoff switch? (Looks like it might not be too hard if the switch is screwed onto the wall, but if it is bolted it could be a pain)

Thanks

ernieh · 09-13-2020, 03:47 PM

Your mechanic "friend" certainly didn't do you any favors. A classic example of "if you don't have the time to do it right, how will you find the time to do it over"? No MH that I've ever owned would crank with the chassis batteries disconnected. In fact, some mfgs disconnect the grounds instead of the hot leads. Good luck!

ProjectPro · 09-14-2020, 05:21 AM

Thanks for the reply, Ernie. You may be right, but had he just removed the original cable from the starter it still wouldn't crank without the disconnect switch being on. There wouldn't be power to the ignition switch, which means no power to operate the solenoid, even with unswitched +12v being present at the starter. Still doesn't make it right...

garykk · 09-14-2020, 08:55 AM

The rotary switch should be an easy fix. Two cables and a couple of screws holding it to the panel.

ernieh · 09-14-2020, 05:33 PM

It sounds like you have answered your own question and learned something in the process. Congrats.

Arch Hoagland · 09-14-2020, 05:41 PM

Quote:

Originally Posted by garykk

The rotary switch should be an easy fix. Two cables and a couple of screws holding it to the panel.

I had to replace my plastic rotary cutoff switch...great fun...NOT.

It was a pain getting to the back side.

All I could find were the same old plastic rotary switches which I eventually bought.

I absolutely hate plastic anything.