2002 Merc 150XR6 Voltage Issue (or maybe not)

[Mark Hofman]

Was out on Lake of the Ozarks last week crappie fishing. Coming back to the dock for lunch, I got an infrequent alarm (high pitched beeping, short and sporadic) from my voltage gauge. I noticed at 4,600 rpms it was reading a shade over 14 volts - call it 14.2.

At the dock I rechecked and tightened the terminal bolts (wing nuts). No beeping after lunch, but the meter was still reading 14 even. At idle it would start around 12.4 but creep up to 14 in about twenty seconds. At 1,000 rpms it would still read 14 even.

Here are my thoughts for causes and corrective actions:

1. Dying cranking battery - load test it first and replace if it fails.
2. Dirty battery connectors and terminals - clean, coat with dielectric grease and reconnect.
3. Voltage regulator/s - inspect for discoloration, scorching, etc. and replace if damaged.
4. This is normal and it's only because I've not had the boat out in a while that I'm overly concerned by an unfamiliar sight - relax and enjoy the fishing.

What am I missing and what would you recommend?

 

[cq]

I guess I am confused, you have an alarm on your volt meter? I would also check the connection on the volt meter and with a volt/amp meter verify that the volt meter is correct.

cq

 

[Mark Hofman]

Apparently I do. I get a high pitched beeping or squeal when it goes off. It's annoying, but it sure gets your attention.

I hadn't thought about checking with a volt meter. Great suggestion! Thank you! I'll have my certified electrician father-in-law check to make sure I do that correctly.

 

[cq]

I keep one in the boat, you can get some very good ones that are inexpensive. Just a small pocket size read volts AC/DC, Amps AC/DC, and Ohms resistance.

cq

 

[Scott Hammer TOXIC]

Just for grins, what was your Water Pressure and did you check the oil reserve(s)?

 

[Mark Hofman]

Tox, my water pressure was nominal, and I had replaced the oil reserve cap assembly (which draws by vacuum from the main tank under the rear deck) the previous time out. Before we went out this time, I made sure both tanks were full. The beeping alarm was an electric-system issue, which I figured out later, because the cranking battery is the one tied to both the ignition and the voltage gauge. It's the same beep I get when I first turn the key to start the motor. I have yet to find time to pull that cranking battery and take it for a load test, but cleaning the cable connectors and re-tightening the connectors stopped the beeping.

My bigger concern is whether the voltage at idle, and the slow creep up to 14.2 even at idle, is normal or whether it is a sign of a failing regulator.

When I get back from our Colorado vacation, I plan to take the boat in to the dealership and have them give the whole thing a pretty good inspection and run the motor in an effort to duplicate what I was seeing. I just don't have the spare time to play shade tree mechanic with it.

 

[AirForce]

At idle it shouldn't be more than say 12.9 and 14.5 around 2000 rpm. But from your first post, the 14.2 would indicate normal to me except that you said it was creeping up at idle. You should NOT be using wing nuts on your batteries. SS nuts with the biggest wire on bottom and finish off with the smallest wire. Make sure the connections are very clean and protected

 

[Scott Hammer TOXIC]

Just be careful with the SS Locking nuts that you don't overtighten and break a post loose.