How to check alternator??

[hot_rod]

How can I check my alternator, when it's on the boat it dosen't appear to be charging according to the gauge. I took it off and took it to the shop and they said it was charging they said clean connections it should be ok. Did that, still same. Will this work to check(If I start the boat and disconnect the battery, if the boat stays running Is it charging) if not how can I check it??? HELP!!!

[fryzll]

Hey hot_rod, is it a standard G.M int. reg. alternator and if so is it still a 3 wire or has it been converted to a 1 wire?

[HammerDown]

I would check it with a volt meter off the Batt. with the motor running.That will tell ya if the guage in the boat took a crap,or bad connection.

[hot_rod]

It's a two wire one goes to the + side of bat. the other(exciter wire) to ign, Has internal reg. Im pretty sure the gauge is working, when you turn the key on the voltage appears to register.
[This message has been edited by hot_rod (edited September 28, 2001).]

[fryzll]

If you check it w/ a volt meter and its not charging and you do have power from the ignition for the exiter then HMMM. This might sound stupid but try running a ground jumper from the neg on the battery to the body of the alt. My buddy had this prob when he had his alt. body powdercoated and he had alot of paint on his block but his was a marine alt. If yours is a G.M. alt then the wire next to your exiter wire needs to loop back to the bat terminal on the alt. Without that wire hooked up, the regulater does not pick up a signal hence no charge. Hope that helps.

[hot_rod]

It was working the way it's hooked up, I checked for ground with a continuity meter and there appears to be ground where would I connect a meter to check what about the disconnect battery method??

[fryzll]

Dont use the old "TAKE IT OF AND SEE IF IT RUNS" method. You can create a voltage spike and kill the reg. Why do you think its not charging? Does the battery keep going dead? Ive seen guages go bad and only read around 10 volts when its actually charging 14. With the boat running hook the + side of the meter to the bat terminal on the alt and just ground the - side of the meter to the battery. Also double check your ground from the battery to the block for any corrosion, that will screw up everything also.
Chris
P.S. whats your excuse for not being at the river? Im in a wedding so yours better be pretty good http://free.***boat.net/ubb/biggrin.gif

[Oldsquirt]

The "disconnect battery" method should not be used. You risk damaging the alternator(if it isn't bad already)or any other electrical components that might be sensitive to voltage spikes, such as stereo equipment.
I see Chris beat me to that answer. http://free.***boat.net/ubb/smile.gif
Also, you should verify that you are getting a 12 volt signal in the IGN wire to the alternator.
Is baot equipped with a voltmeter or an ammeter?
[This message has been edited by OLDSQUIRT (edited September 28, 2001).]

[hot_rod]

I don't think it's charging because the gauge dosent show a charge battery Has not gone dead but sinc I can't get out and walk I diden't want to find out that way. BTW I'm at the river (I can see it out my back door) http://free.***boat.net/ubb/biggrin.gif http://free.***boat.net/ubb/biggrin.gif http://free.***boat.net/ubb/biggrin.gif

[fryzll]

Now I hate you, that last remark was totally uncalled for http://free.***boat.net/ubb/biggrin.gif Now I have to start drinkin just so I feel better about it. Why cant you walk, I know your not stumblin drunk yet, ARE YOU ? Oh well, have a good weekend bud.
Chris

[hot_rod]

Thanks for the help, got a new alt, and that did the trick.
I guess the place I had check it has CRAP for test equipment.
Hi Ho down the river I go!!

[BLOWNDRAGBOAT]

HEY HR..I haven't spoke to ya in awhile. Hows the boat running? I was reading the threads and wanted to tell ya this. NEXTTIME your altinator or charging system is acting funny than simple start the motor and connect a multimeter to your battery terminals. Make sure its set up to read DC volts. While the engine is running and your reading the multimeter, slowly bring it off idle and slowly rev the motor and hold it a second or 3 @ 1800 rpm. You SHOULD be seeing the multimeter climbing in voltage as the engine rpm increases. Assuming your battery is already holding around 12-13 volts, you should see 14-16 volts (or there about depending on altinator and battery being used) on your meter. If thats what your seeing than the altinator IS charging. If it stays at 12 and or drops in voltage while your reving the motor then your NOT charging. Just a little tip to save ya some time nexttime. NEVER DISCONNECT THE BATTERY WHILE THE ENGINES RUNNING. Still got those heads forsale?