Engine Question

Is a 1984 Merc 50hp equipped to charge the starting battery while it’s running?? Mine doesn’t and I dont know if its supposed to or not…

Thanks for any info.

Tim

Yes…they have a small alternator but don’t charge much at an idle. Short runs, even at high speed, do not do the trick after a while. With all the graphs and pumps etc. running off the main starting battery, you can eventually lose the charge. That’s why I use deep cycle batteries for all my starting batteries.

Thank you Steve. My battery is actually a “dual purpose” that loses its charge after two or three trips. I forgot to mention that. I dont know if it makes a difference or not.
The only electronics I run are one graph, my trim, and my nav lights. I usually put close to 10 or more miles on the boat every trip at full throttle. I THINK my battery is not getting charged… is there a easy way to check with a multimeter or something??? Maybe its charging is so minimal that I just dont notice it.

Sounds like the magneto is bad.

Can it run with a bad magneto? Mine runs fine. I looked at the parts list and did not find anything called a magneto but I found an ignition trigger and a stator on the list. Is it one of these??

Thanks

Start it up and pull a battery cable off. If it dies then you know that it is your alternator. If it keeps running then you know that you need a new battery or have a bad connection.

Your alternator should charge even at an idle. You can put a volt meter on it and that would tell you if it is weak.( then it would be a regulator issue, most of those a built into the alternator. Same result, new alternator).Any shop or buddy that is mechanically inclined should be able to do that for you.

Good luck.

Its a stator, not an alternator