Gauges going down I have an 06...

[DaveKola]

Gauges going down

I have an 06 38 Sundancer with twin 8.1’s.  Recently all the port gauges including the port half of the vessel view will quit.  Later, and at varying lengths of time, they will come back.  No change in performance.  Gotta be a loose or poor connection somewhere. Where should I begin my search?

[wingless]

Welcome to the forum.

It is possible to use a voltage meter to identify the problematic connection while happening, or to use a carbon pile load to aid the process, but why bother?

My suggestion is to first disconnect the battery negative terminals, then sequentially disassemble, inspect, clean and properly reassemble each battery negative and positive terminal, from the battery, through the contactors, the power distribution, to each engine.

The Mercruiser Factory Service Manual (FSM) specifies usage of liquid insulation on all those power terminals. I have that on all my connections, as the finishing step.

My 100% speculation guess is that the problem is on the main engine power lugs.

[DaveKola]

Thanks! I will start there and work my way towards the motors. Will post the results.

[PeterG1]

Look for a loose ground connection

[Lucky_five]

Had the same issue turned out to be the ecm was bad

[PeterG1]

Did the engine not run with the bad ECM

[Lucky_five]

runs then goes in and out while driving so as the gauges

[Lucky_five]

Swap the ecm from one motor to the other and see if the other motor will act up then u will know trust me took us a year to figure it out Everyone thought was ground or harness

[LADONNA]

There is a big connector at the front of the engine. Take it apart and clean the pins.

[Alumofcu]

I have a 500 and my port side does same. At clutch speed the behave fine. Only when I start to cruise they drop and come back. I’ll check that plug.

[Alumofcu]

@David Kolakowski@John Caradonna I reseated that plug on front of engine. The waterproof rubber grommet had dislodged and was interfering with one of the pins. Moved it out of the way and no issues with temps and pressure gauges. My port side tach still drops out. Do you know where that plug is?

[DaveKola]

Unfortunately, I am out of the water and stored for the winter. No way to verify my success until spring!