Too much charging voltage on my Mercruiser 325

[donwhiteside]

Hello All- I'm new to the board, and boating. Recently bought a 1973 Cruise-a-Home with a Merc 325 engine and III I/O. Working thru a number of items, but right now I am stumped by the voltage regulator. Voltage on a digital voltmeter shows charging voltage of 15-16 volts. Seems like the voltage regulator (Merc # 37707) needs replacing. <br /><br />I did a search and found very valuable info from a previous post- http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=010399#000000 <br /><br />My question is: Convert to a 1 wire alternator? What about the voltmeter at the dash? Will it still work? <br /><br />Any and all help is appreciated!<br /><br />Don in Northern California

 

[trog100]

Re: Too much charging voltage on my Mercruiser 325

i think a dc voltmeter is a dc voltmeter.. it just reads the voltage in the system.. what kind of alternator u have shouldnt affect it..<br /><br />trog

 

[donwhiteside]

Re: Too much charging voltage on my Mercruiser 325

OK, that makes sense. An ammeter would be a different story. <br />I'm still worried about taking the voltage regulater out of the system, for fear I'll disconnect something I need. This is an electronic "Thunderbolt" ignition, and according to the wiring diagram, the "white" lead out of the voltage reg, goes to the ignition switch box.<br /><br />Not sure what to do...<br /><br />Don

 

[trog100]

Re: Too much charging voltage on my Mercruiser 325

only guessing here but the white wire probably feeds the excitor/field coil.. u need a positve 12 volt feed to the field coil for the alternator to work.. it probably goes live when u turn the ignition on..<br /><br />apart from this the only other wired needed is the one that goes off to the live battery terminal..<br /><br />i think the field coil could also be fed from this one wire.. it probably isnt but it could be..<br /><br />again i am not overly familiar with your particular ignition system but like the volt meter i dont think your alternator should affect it.. someone will correct me on this if i am wrong i hope..<br /><br />trog