How can I tell if the charging system is working properly

[molsenice]

I have a 95hp '67 Mercury Outboard serial #2124524. This past May, I recieved the boat as a gift from my pop and connected the battery backwards, the red cable is a very dark shade of maroon. This mistake cost me close to $300 and ten times that in heart felt sorrow for hurting "pops boat" - I ended up replacing the switchbox and the rectifier and ended up learning about IBOATS in the process. I do have a manuel and am slightly mechanicaly inclined (Shop teacher). Never really got into trouble shooting charging systems so heres a couple of questions before I start to tinker. 1) How long will a 95hp Merc run on a fully charged battery before craping out? (my harley will make it about 300 miles - 4hrs.)Also, question 2)should I have replaced anything else - never though to check that the boat was charging, I had soild my shorts with the fact that it was running. 3 When checking that the charging system is working on my bike, first I did a voltage check with the engine off, then turned it on and check the voltage - on the bike, it was .03volts less and turned out to be the voltage regulator. Is this how I should go about checking the Boat??

 

[Yepblaze]

Re: How can I tell if the charging system is working properly

Yes, put a voltmeter on it and read the voltage while stopped and while running at elevated RPM's

 

[molsenice]

Re: How can I tell if the charging system is working properly

thanks will do

 

[molsenice]

Re: How can I tell if the charging system is working properly

Ok, unlike the test on my bike, the results now seam OK. Initialy voltage on battery, motor not turned on (12.81) - battery and motor not touched for ~18hrs. Motor starts perfectly, voltage now reading 12.68 - I initialy think o-not charging, put motor into gear (low speed) water sloshing out of tank - I'm laughing, voltage now reading 12.74, witht the "4" changing between 4,1,3,5,4 (kinda like a gas pump). Put engine into neutral, voltage steady at 12.74. Turn motor off, battery reading 12.74. Ran test: voltage w/motor off, then with motor on then motor in gear, five more times, and the voltage remains steady @ 12.74 - system looks good? - No? now to figure out why battery was dead after being fine for the entire season - It is possible that where I docked the boat the the kids who "did me a favor" by taking the boat out periodicly to empty the water out may have left the ignition on and only turned it off when they put the cover back on. I could easily see that they would over look this detail, they never even mentioned that they had gotten the water out by any other method but bailing, their Dad mentioned they had taken the boat out. Nobody owning up to leaving the ignition on. No harm don, but do have a haunting feeling that I am missing something, any chance I have?

 

[Barnacle_Bill]

Re: How can I tell if the charging system is working properly

Check your rectifier according to your manual. You may have an open diode on one side.

 

[Laotzu]

Re: How can I tell if the charging system is working properly

If I'm reading your posts correctly, your trying to determine charging voltage with the motor in a tank? You really should'nt rev the motor in a tank if that's what your doing. Witout drag on the motor high rpm can blow some parts off it. Besides, the voltage won't climb at idle rpm unless you have a very low battery charge to begin with. A Properly charging system should be around 14.5V at higher rpms.<br /><br />Jerry

 

[molsenice]

Re: How can I tell if the charging system is working properly

Laotzu - yep - it was in a tank - but just in gear, not reved - never got close to anything above 12.74v runing or in gear or off - so I can assume I'm not yet there. IBNFSHN - Will refer to the manual, rectifier is new but have had new stuff thats bad before on other things, any idea how to test dioad?

 

[molsenice]

Re: How can I tell if the charging system is working properly

Ok - new question, same topic. In the Manuel, I start reading and instantly feel clueless. It mentions a Magneto Analyzer allong with the testors part #. Will be doing a search to see if this is something I can do with a decent multimeter. Or one of you guys may have been there, done that and could explain it to me. Don't ya just love self education?, at least this time I vow to no do anything till I understand what will happen ether way.