Battery charging problem

[ethyl]

My classic 18 has a 260 hp 350 chevy Mercruiser powerplant that has been charging fine but last summer I was not getting a charge( voltmeter shows under 12 volts with ignition on and with engine running it drops) I had the alternator checked and it was o.k. I even replaced the alt. with another which tested o.k. with no change. I checked the wiring harness for poor connections and did not find anything obvious. Am wondering if there is a seperate voltage regulator on these engines or if this is part of the alternator. Thanks in advance for any info. John

[MOP]

You may just have a bad gauge, just because the needle moves does not mean it has not lost its electrical value. There is no separate regulator. Have you tried an independent volt meter? Have you separated the main harness plug? Separating the plug should be done when ever you have engine related electrical issues, attention should be paid to the male end of the plug. If the prongs are discolored you will need to clean them, a strip of 400 grit paper lightly pulled through does a nice job. You will notice the prongs have a split in them, being careful take a thin sharp blade and open the gap very slightly. Opening the gaps will increase contact within the plug, it may fix your problem it has on occasion for me.
Phil

[ethyl]

Phil, thanks for your reply. Actually, the boat had an ampmeter and my battery kept going flat so I installed a voltmeter, tried a new battery and spread the prongs on the harness plug. I did not clean the female contact surfaces though and will try this. Thanks again, John

[MOP]

Electrics can be a pain! Try this, with everything turned of remove the battery cable then touch it to the post. If you see a spark even ever so slight something it drawing current, finding it can be time consuming.

[ethyl]

Thanks Old Fart, I will give this a try.