Mercruiser 4.3 starts only when a DMM is connected on the battery poles

[Mattias-Sweden]

I have a strange issue with my Mercruiser 4.3 2006 mounted in a Utter C66 Exclusive.
The power trim will not work neither will the instrument/engine start when I put the ignition key in run.
If I attach a DMM to + and - directly on the battery, everything works, power trim and the engine starts. I have actually tried two different DMM and both on/off with the same behavior. The batteries are OK, and i have also tried with different batteries.
I have checked the terminals that I can find.
I have a techmate pro and checked the faults and there are non.

Please help me in finding the root cause.

BR
Mattias

 

[Bondo]

Ayuh,...... Welcome Aboard,....... Have you removed the cables, 'n cleaned everything to shiny Clean metal, 'n reattached 'em yet,..??..??

 

[Benny67]

Check your grounds...every one of them...twice

 

[Mattias-Sweden]

I have now removed every cable joint that I found in the boat/on the batteries/on the "dashboard" Cleaned the surfaces and re-attached. It works now. I think I was a bit tricked by the strange behavior with the DMM.

Thank´s!

 

[Scott Danforth]

now seal the connections with marine electrical varnish (available at most battery and marine stores)