Mercury 115hp 1973-up 6cyl charging system???

[peternol]

I just want to know which parts in my charging system I have to fix first in order of the sicknals its gave me.<br /> A: When I turn on this engine its register 10.3 amp. at the battery poles but the battery its new and working excellent on my car registering 14.6. Here's when I know something in this system its not charging well my battery.<br /> B: When this engine its running, If I take any terminal from the battery out the engine turn off, when this happen in a car you probably know its the alternator. What ist wrong here?<br /><br />Thanks in advance for any help.

 

[mellowyellow]

Re: Mercury 115hp 1973-up 6cyl charging system???

running motor without being attatched to the<br />battery can seriously damage your motor.<br />get a manual and trouble shoot the problem.<br />it's usually the rectifier and manual will tell<br />how to test.

 

[Gold Bear]

Re: Mercury 115hp 1973-up 6cyl charging system???

la-viejita-73 <br /> <br />As mellowyellow said, you do not want to remove the battery cable from this engine while it is running. Your ignition uses battery power produce spark. Removing the cable can damage the ignition switch box.<br /><br />It sounds like your alternator / charging system is not working. When the engine is running you should see about 13 volts, and that will increase to about 15 to 17 volts under power.<br /><br />Under the flywheel there is an unregulated alternator that produces alternating currnet. That is wired to a rectifier to make 12 volt DC power to charge the battery. It is most likley the rectifier is bad. A new rectifier cost about $35 from your Merc dealer.<br /><br />The most common problem with the alternator is insulation worn / flaked off the wiring, close to where the wire enters the alternator housing. If you look up at the alternator (it is tucked up under the flywheel) on the right side of the engine you may be able to see if this is a problem. <br /><br />Get a manual and trouble shoot the rectifier first.<br /><br />Good Luck, Gold Bear