Intermittant electrical problem

[JackH]

I’ve been trying to diagnose and intermittent electrical problem on my 95 370DA. The port engine seems to lose electrical power intermittently. The engine will start and run properly if I use the emergency start switch – effectively running the engine from the starboard power. If I release the relay switch, the port will cut out immediately. Without the emergency switch engaged, the port engine will intermittently have zero electrical power (i.e. No buzzer or gauges come on when the ignition is turned on) or full power – the engine fires right up. At first the engine would only run a couple of minutes then quit. After sitting a little bit, it would fire right up again.

The batteries do not appear to be missing any water and are two years old. I cleaned just about every contact I could get to and thought all was fine after running the engine at the dock for a half hour or so. Off I went into the C&D canal only to have the engine quit just a couple miles away from the dock. Bringing her back to the slip in one engine in a moderate breeze is always fun – my wife and 10 year old son did a good job of fending!

When I got back to the dock, the volt meter on the dc electrical panel showed 8 volts for the port side, leading me to suspect a battery problem. My next step is to get a battery load tester and hydrometer to check each battery individually. There are four batteries, presumably two for each engine. Am I on the right track with this? Is there anything else I should be checking? I’m really hoping to find a hard failure to make sure I’m not chasing an intermittent problem all season.

Thanks, Jack
97 370DA
Bear, DE

 

[xravenx]

I also have four batteries..........one only starts the port motor, another one only starts the generator and the last two are hooked up together and they start the starboard motor and are for the house.

John

 

[JackH]

John,

That's great information, and should help isolate the problem. Was scrating my head a bit yesterday to figure out which batteries where for what.

Jack

 

[J Levine]

My 4 batteries are wired as John has indicated above. You might want to check the battery switch just to make sure it does not have some issue that is causing your problem, it is mounted under the sink in the cockpit.

 

[fc3]

Assuming that the connections at the battery are clean and tight and that the battery switches are one, you need to get a good voltmeter and do some systematic checks.

First check the batteries. If weak, rechange. If they don't hold a charge, replace. Then check power to the engine. Check the fusible links. Check that the alternator charges. If the alternator was operating while there was no battery attached, the rectifiers are probably destroyed. If you have a battery isolator, check the rectifiers in the isolator.

Best regards,
Frank

 

[JackH]

Frank,

Tried to shunt the battery switch on the back using a screwdriver with no change. Just ordered a hydrometer and battery load tester online. Mother's day will be spent working on the boat. My wife has come to expect nothing less!

Where might the fusable links you mention be located?

Thanks,
Jack

 

[xravenx]

Was scrating my head a bit yesterday to figure out which batteries where for what.

Jack

Jack,

I found that all my red cables from the batteries were labled as to what they were for, yours should have lables on them.

John

 

[fc3]

The fusible links are on the starter's battery terminal. It's rare, but not unknown for the fusible links to form intermittent contact with the crimped on connectors.

Best regards,
Frank

 

[dc380]

The Boat aside of me had a very similar problem, last spring. After checking eveything Frank just mentioned, we started checking the battery cables. Turned out to be a corruted batter cable, in his case it was the black ground.

 

[Hwillcockson]

JackH -

I have a '97 370DA and had the same problem with my port engine cutting out when I fist launced last Spring. Luckily I had a buddy that is a Master Electrician and is used to dealing with elecrical troubleshooting. From the DC control panel I had power to the starboard engine (and house loads) but when I pressed the momentary switch to check the voltage from the port battery bank the needle would drop from 13+ volts to zero.

From there we went into 'troubleshoot" mode and went from the battery connections all the way through the DC Breaker Box (engine compartment with resetable trips) and from there to the wiring to the Control Panel (cabin). We found a loose wiring harness connector behind the dashboard that when we put pressure on it we got power back and when we let go we lost power on the port side.

Unscrew the section of the dashboard with the Tach's/gauges on it and you will find a few wiring harness cables and connectors where the harness from the DC Breaker Box meets the harness to the DC Power Panel in the cabin. Wiggle the connector for the Port side and see if this works.

After finding the problem we used small tie-wraps to hold the harness connector together as best we could. We haven't had a problem since.

I hope this helps

 

[JackH]

Thanks to everyone for your advice. I finally got to the bottom of the trouble. The main engine harness connector (large round black connector) had some corrosion on the pins. Cleaned the connector and all has been running just fine.

Jack

 

[njb3636]

I am having a very similar problem with my 1996 37' sundancer. There is intermittant no power to the ignition, gauges and cabin meter for the port engine. When this occurs, there IS power to the starter as well as the breaker box in the bilge. I haven't checked any connections in the dashboard but i will check behind the tachs next. Where are the other connections that could cause possible problems?

 

[fwebster]

The wiring harness you both mention has several pieces to it.......from the main panel to the bilge along the bulkhead, from the bulkhead to the engine, from the bulkhead to the panel, from the panel to the actual switches and gauges. Each one of the parts of the wiring harnedd is connected to another with male/female terminal blocks. The pins in those terminal blocks are not molded in. The press in and can slip back away from the mating part in the other terminal block thus preventing a good connection. While you may have gotten your boat running, I'm betting that your fix...ie. cleaning the pins or the wire tie.... is temporary and thet you will need to eventually take the terminal block apart and properly position the pins on both the male and female sides.

This one is an easy and free fix, and you both have already done the hard part......finding the offending terminal block. I have spent days finding all the terminal blocks and looking for the loose pins on mid 90's Sea Rays before.