Battery not being charged

[steelebob]

My 3 cyl 1989 Mercury 70 hp (ELPT0) OC134764 Model # 1070412GD works fine as long as I charge the battery myself.
Anything I can do to check it to determine what to do next?

 

[Barnacle_Bill]

Re: Battery not being charged

Test your rectifier/regulator. Instructions are in your manual.

 

[BayouRunner]

Re: Battery not being charged

My 1990 115 had the same problem...after the power pack went out. I went to NAPA, and got a rectifier, which was WAY cheaper than getting one from Mercury. Now my battery is being charged with 15+ amps. I've taken the boat out 3 times since I replaced the rectifier, and have put it on charge before each trip. No need, as the battery charger reads 100% every time.

 

[Dave1027]

Re: Battery not being charged

I went to NAPA, and got a rectifier, which was WAY cheaper than getting one from Mercury. Now my battery is being charged with 15+ amps.

How much did it cost and what brand is it? Was it the same as the Merc unit? How many terminals does it have?

 

[MikePaauwe]

Re: Battery not being charged

I had identical symptoms with my 135 Blackmax.
The rectifier was OK and so was the alternator coils. The problem was the voltage regulator.
i ended up replacing it with a CDI unit. The CDI unit replaces the regulator and rectifier with a single module. Works great.
Rectifiers and coils are easy to test with a multimeter so start there. Expected values are in the manual.
Regulators are not so easy, but if your system voltage goes up at all when you rev the engine I would suspect the regulator.
Good Luck