Voltage Gauge Surging

[texsun]

I have a 96 Larson 3.0 VolvoPenta. The voltage gauge works fine at idle but after I've been cruising (3500-4000 rpm) for about 15-20mins the voltage gauge will start dropping toward 10 then 8...and then suddenly jump back to 12-14.
At the same time the Temp Gauge will start moving higher and then suddenly move back to normal.

It never affects the engine in any way. This has been going on for over a year and I would like to correct it.


Thanks Again!

 

[Don S]

Re: Voltage Gauge Surging

Time to start checking all the wiring harness connections between the engine and dash. Probably some corrosion or loose connection somewhere.

 

[thrasher]

Re: Voltage Gauge Surging

As Don says, it sounds like a bad connection somewhere. These are usually a PITA to find. I would start by looking at all the connections on the back of the gauges, on the starter motor and pay particular attention to the multi pin plug that connects the engine wiring harness to the boat wiring harness (I think its called a cannon plug).

Gary

 

[mrw90]

Re: Voltage Gauge Surging

The guys that answered the question ahead of me know their stuff. I just wonder if maybe there's an alternator belt slippage happening. At least on my 5.7, the alternator belt also drives the fresh-water circulating pump. The corresponding increase in temperature at the same time that the voltage is dropping makes me think that something could be going on with the belt.