charging system

[steplift20]

i just installed a new voltage egulator on my 150 mercury o.b and it is not charging,what else could it be.
all the battery terminals are clean and my batterys are good

[phatdaddy]

Could be the stator (under the flywheel) What year merc? Have youhad any trouble with your tach lately?

[steplift20]

your on the money, but the stator is new only about 1 year old. and my tach is not working but i dont know if its because of the tach itself or something else. it never was dependable

[steplift20]

oh its a 1988 150 black max

[phatdaddy]

Even though it is only a year old, I'll bet it is the stator. Every time I have had trouble with the tach, the charging system goes out later. If this is the 2'nd stator in a year, something is causing them to fail. You might be treating a symptom instead of a problem.

[Veeder]

Put the Grey Goose in the water today ('83 cuddy w/200hp black max). On the first run out of the harbor, I smoked my tach. When I got to the dock and shut it off, it wouldn't restart. Found a 20A fuse on the motor that was blown. Changed the fuse out, the motor runs, but the tach is toast. Could this also be a stator problem? Did it overcharge? What's next, and how do I prevent more damage from occurring?

[Airslot]

If the stator is good, the problem is more than likely the rectifier. I've got the same motor.

Airslot

[reelapeelin]

Veeder, was the tach adjusted to match the motor?... ???...

[Veeder]

Yes, the tach was adjusted to match the motor. Tach actually filled with smoke while under way; kind of looked like a crystal balll-and it was telling me my immediate future was about to take a turn for the expensive!

[phatdaddy]

Veeder, do you have a volt gauge or a voltage readout on your gps? IF it is reading 12.5 or above while the engine is running and drops when you shut it down, then the charging system is ok. I had an 83 150 on my boat when I bought it and it put out 16 to 17 volts when charging, but the amperage was very low. My 94 puts out 14.2 when running 1000 rpm or greater, but with more amps. Hopefully it is just a tach problem.

[Veeder]

Put the volt meter on the engine today. Reads 12.5 at idle and when revved. Found that the positive cable was slightly loose on the engine. Also found the the negative cable from my secondary battery had come off the post while underway.

[phatdaddy]

what does the meter read w/o the engine running?12.5 while running dosen't sound like it is charging to me.

[steplift20]

put the multimeter to the battery without starting anything and it read 12.49, started the motor and it dropped to 12.31 and not charging,
the funny thing about it is when i first changed the voltage regulator it was charging the about a hour later it stopped charging
go figure

[phatdaddy]

I don't know if you can pull the individual components and have them bench tested. I think you have to find out the cause, because you have changed out all of the parts (stator, regulator,&rectifier). You mentioned dual batteries, did you add that prior to the problems, or change out a isolater switch?

[steplift20]

no

[Veeder]

The batteries are at 12.5 if the engine is running or not. If I rev the engine...still 12.5....

[Airslot]

Guys, this is too easy to troubleshoot. *Veeder, got a multimeter? *On an 88 merc 150 the rectifier is right above the switch boxes. *It's held on by a screw in the uperleft and lower right corners. *Has 3 terminals on it. *

With your battery switch off, discconect all of the wires from the rectifier, 2 wires on each terminal. *Two reds and the + terminal (lower left), a grey and a yellow (upper right?) and a tan and a yellow (lower right).

THe two yellow wires go to the stator. *You test for continuity between the two wires and then between each wire and ground.

The rectifier is tested without removing it. *There is a series of tests that go between the terminals. *I'd have to have my book to toell you exactly what they were. *A new rectifier is $37.50, a stator is about $180. *Most times when a stator goes it will take the rectifier with it. *Sounds like a bad rectifier to me.

Airslot

[steplift20]

you sound like you know what your taking about
i will change the rectifier,the only problem i have is that i was taking to some one at merecury and they told me it would not be the rectifier because the only thing the rectifier does is change the current from ac to dc or dc to ac you know what im talking about
but i know a wire goes from the regulator to the rectifier and i will change it
thanks
i will let you know how i make out

[Veeder]

Airslot,

Thanks! Changed out the rectifier and solved the problem. Tech said that's why my tach got smoked. New rectifier in place, no problems. Just need to replace the tach. Engine still sounds like a dragster,though..

[steplift20]

hey veedwer do you have the same problem i have because i started this topic and you got the answers