Merc Outboard Not Charging Battery???

[tashit]

My battery seems to die on me about every 3-4 times I have the boat out. At times I do a lot of starting and stopping so the motor ('86 Merc 90 hp) may not have the time to keep the battery charged. However I read that the output from the rectifier should be 13-13.5 V at w.o.t. The graph in my boat was reading 14-15 V at idle and 16-16.5 V at w.o.t. Is this too much? Do I possibly have a bad rectifier or stator? I'm hoping it's just from starting/stopping fairly often but we never had this problem until last year and we've had the boat for many years. Oh, and the battery did hold a charge over the winter and I don't think it's a bad battery. Thanks!

[Meat-Run]

tashit,

I'm not an expert on this but hopefully marine_man will chime in soon to help. Anyways your avator just kills me. I would say that's the funniest one I have seen. Just to good....

mr

[Shack]

I would have battery load tested at local garage or dealer ship. Do not pay to have load tested, they should do it for free. This may not cure your concern, but is a good idea to have checked. Also it seems like you maybe have a voltage regulator concern. You stated "rectifier", this may be the same part. Just another name for same part. If battery fails load test, replace battery. After you do this, the next time you have motor running at idle (in lake or with cups) check at battery term (all cables connected) with mutli-tester. Set to 20 or less volts (20v) and see what it really is charging at. Gauges have been known to show false reading's before. They all have a +/- of 5% accuracy anyways (dealer spec's) and could have more. Some could be dead on. Good Luck..

[tashit]

I'll hopefully get on the lake tonight so I will bring my multimeter and test it.

As for my avatar, I can't take credit for it because I found it on another forum but I too thought it was hilarious...I just had to use it.

[Meat-Run]

I swear I was stairing at your avatar (10 minutes) and saw the cat reload, is that possible!?!?!?

mr

[marine_man]

Is your tachometer working? Usually when a rectifier goes it will completely die and you'll use your tach as a result of that. Your charging volts sounds awfully high to me though - 16v? Are you sure you're reading that right?

marine_man

[tashit]

My boat doesn't have a tach. I hooked my Lowrance up to the starting battery the last time I was out and it was reading around 16.5 V at w.o.t. I wasn't able to get out last night but I will for sure this weekend and I'll take a reading with my meter instead.