25 merc ob not charging battery

[RICHARD PEARSON]

Battery will not charge. It will run without battery cable hooked up.<br />How do I test it for the problem.

 

[Ben Konopacky]

Re: 25 merc ob not charging battery

Richard Pearson; your ob's sn# & mod # please. from those we can get the year and some help.

 

[RICHARD PEARSON]

Re: 25 merc ob not charging battery

2000 25 hp OT114191

 

[RICHARD PEARSON]

Re: 25 merc ob not charging battery

model # 25EL

 

[FlyBoyMark]

Re: 25 merc ob not charging battery

FIRST....Check battery connections for corrosion and check terminals on motor for loseness.<br />SECOND...Are any of the cells dry or exposed?charge battery overnight(make sure cells are full if not fill with distilled water only).<br />THIRD....Check with hydrometer after charging(less than 75% means battery is begining to get weak).<br />FOURTH...Start engine and at fast idle measure voltage at battery.<br />Get back to us with info..

 

[RICHARD PEARSON]

Re: 25 merc ob not charging battery

no voltage increase when meter hooked to battery and motor speed up.<br />no voltage on red wire coming from motor[motor running and wire disconected from batt.]

 

[FlyBoyMark]

Re: 25 merc ob not charging battery

POSSIBLY the charging coil has gone out on you. You will probably have to pull the fly wheel. But first lets verify its bad. To check if the coil has shorted to ground, disconnect all leads to the coil and use meter to check for ground faults. Also, try to run the motor with the wires from the coil to the rectifier disconnected and measure votage with meter set to AC VOLTAGE. There is a fuse on some of the Merc engines for the electic system, you might want to check it to jus incase.<br />$35 investment in an ORGINAL Mercury Service Manual is highly recomended.