Mercruiser 5.0 I/O Electrical Problem

[rjd7]

Hi Everyone...<br />I'm a first year boater (2000 Sea Ray 240 Sundancer) and had a great summer, but now I'm seeing some funny electrical things. The battery gauge always stays around 14v, but the other day I was out for a while and noticed it was just under 12v and the Tach was way off... showing around 5000 rpm when I know it was turning 3500 or so. As I brought her in, I noticed that the voltage was continuing to slowly drop as well. I'm going out to take a look at her, but thought I'd get some advice about what to look for. I'm guessing its bad ground, batteries, alternator or maybe a voltage regulator...any suggestions where to start?

 

[tommays]

Re: Mercruiser 5.0 I/O Electrical Problem

the first thing to do is buy a multi meter and check the real voltages the guage isa guide but not that accurate<br /><br />a battery should hold about a 12.6 to 12.8 volt charge<br /><br />when running the voltage at the battery should be around 13.7 to 14.2 more or less<br /><br />your problem could be as simple as a lose alternator belt or bad connection at the battery<br /><br />start with real meter readings and checking the connections on the alt an battery and go from there<br /><br />tommays

 

[Don S]

Re: Mercruiser 5.0 I/O Electrical Problem

One place to start looking at is anyplace you have just installed something or done some work. Perhaps you loosend a connection by accident or ran a screw through a couple of wires or ?????<br />For sure you wouldn't be the only one other than me to do such a thing.

 

[DayCruiser]

Re: Mercruiser 5.0 I/O Electrical Problem

I was discussing on here there my guages were going whacky. The amp were shown to be going down. The oil pressure way up. The trim was down. All these happen at the same time. Before just the amp registered wrongly.<br />So I went for a out in it yesterday and started wiggleing some wire ect. I push in the cylinders around the engine. I came to the last of the 3 cylinders. It was on the left rear of the engine with wiring going to the box attached to the right side of the engine. I wiggled this one and push it in and the guages jumped back in place. The cylinder has a short in it thats effecting the entire wiring harness. I went back to the dock and unplugged it and plugged back together to make sure the connection was secure. That helped but the guages still screw up but then go back into place and they jump sometime--but this is no where near as bad as it was.<br />Maybe you should look at these cylinders as part of your problem? If it effect more than one guage it has to be something main going into the wiring. The cylinder went to the electronic ignition and to the box o nthe right side

 

[rodbolt]

Re: Mercruiser 5.0 I/O Electrical Problem

hello<br /> not knowing what you refer to as a cylinder, I will state that we had a lot of corrosion problems at the main engine harness plug and the ring terminals on the 50 amp main harness circuit breaker. if it corrodes it will do flakey things. check all of your connections for corrosion and mechanical integrity.

 

[rjd7]

Re: Mercruiser 5.0 I/O Electrical Problem

OK... Thanks to your suggestions, I found the culprit... a corroded wire to the alternator. $2 for a new connector and everything is working perfectly.<br /><br />Thanks again for all the advice!

 

[record hunter]

Re: Mercruiser 5.0 I/O Electrical Problem

make sure you did it right and I hope you heat schrunk the connector.

 

[rjd7]

Re: Mercruiser 5.0 I/O Electrical Problem

I appreciate the cautions. I did use a marine grade connector with an integrated heat shrink tube. But I'm curious... is there something else I should be concerend about? Does that particular connection get hotter than most or is it subject to some other abuse?<br /><br />I'm pulling her out of the water for the winter so I can re-do the connection if necessary.

 

[tommays]

Re: Mercruiser 5.0 I/O Electrical Problem

you did it right people get concerned because some DIY people dont seam to realize the inportance of doing repiars with the orginal type of marine part <br /><br />many people would have gone to the auto store and used a standard connector and then wonder why it failed so fast<br /><br />tommays

 

[highaltitude]

Re: Mercruiser 5.0 I/O Electrical Problem

if the "cylinders" you are referring to are actually pin connectors-you should be able to spread the male pin to make a better contact when the two halves are connected.