75 hp merc charging problem HELP NEEDED

squidkid

Cadet
Joined
Aug 12, 2003
Messages
9
sorry guys, the motor is a 1996 75hp mercury outboard.<br />i originally thought that my charging problem was due to the batteries but after fully charging my batteries and having them load tested i determined that my batteries are not the problem.<br />i was told that they should read in the 12-13 range when the motor is not running and a few points highr when the motor is running. mine read the same regardless of the motor being ran. the volt meter that i borrowed doesn't read in the 10ths.<br />i can only assume then that the problem lies within my motor now, but i have no clue what to check next to narrow down the culprit.<br /><br />what should the next check be?<br /><br />does the fact that my motor continues to run with the battery disconnected(long enough to replace it with a fresh one) make it easier to indicate the problem?<br /><br />can running the motor without a battery hooked to it for a ground ruin a rectifier in just a few short moments(a minute or two)? the reason i ask is because i think that i have had this problem for awhile now. i just assumed that when i lost power to my electronics(graph, gps radios) but my motor kept running was that i had a bad battery or severely drained one.i would then hook up my spare battery and finish out the day. i would go home and throw the chargers on and they would be ready to go the following week. i guess what was happening was that all my electrical use was coming straight out of my batteries with no help from my motor. <br /><br />is the rectifier something that can be replaced with relative ease?<br /><br />can i still use my boat knowing that my batteries are going to be seriously drained BUT without causing any further damage?<br /><br />thanks in advance
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: 75 hp merc charging problem HELP NEEDED

Either your Stator or your rectifier is done. IF you have a black stator...IT is most likely the problem.<br /><br />On a good note...the new stator will be a 16 amp charging one :) <br /><br />TMD
 

squidkid

Cadet
Joined
Aug 12, 2003
Messages
9
Re: 75 hp merc charging problem HELP NEEDED

thanks doc, <br />how do i test to determine which is shot?
 

squidkid

Cadet
Joined
Aug 12, 2003
Messages
9
Re: 75 hp merc charging problem HELP NEEDED

hey doc, <br />is the rectifier easy to replace myself?
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: 75 hp merc charging problem HELP NEEDED

The regulator/rectifier is easy to change.<br /><br />The only way you will be able to test is by checking for continuity between the yellow leads on the stator. <br /><br />If there is NO continuity...the Stator has failed. If there is Continuity..its likely that the voltage regulator is bad.<br /><br />Are the battery posts tight? Has anyone hooked the battery up backward?<br /><br />TMD
 

andrewkafp

Lieutenant Commander
Joined
Mar 15, 2003
Messages
1,668
Re: 75 hp merc charging problem HELP NEEDED

And..<br />Don't ever run it with battery disconnected or reverese polarity. Merc Manual states that it will cause damage to the rectifier.<br />As TMD say's.. 'Test both components, but the rectifier is easier and cheaper to replace.<br />So keep your fingers crossed. :eek:
 
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