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115hp four stoke overcharging

C

captal

Contributing Member
OK I think I stumped the Yamaha mechanic so I need some help from the pros on here! I have a 2001 Yamaha 4stoke. Never had a problem till recently. My VHF turned red, started beeping, and displayed "Battery Voltage too High". Noticed the battery voltage at 14.8. Usually with a full battery and running it stayed around 14.2-14.5 volts. If I turned on a pump or lights or something it would hold around 14.5 but as soon as I turned off the load it would shoot back up to 14.8. Got home did the usual, checked and cleaned all connections, used a good digital meter, and checked the battery. At idle on the hose still held at 14.8. Went to the dealer and he advised the regulator was probably bad. Bought a new regulator ($150), put it on, same problem. Changed the battery, seemed to take longer to charge up but still same problem. Went back to the dealer and he said that he has no idea what's wrong but for $80 an hour he would "play with it" and see what he could figure out. I don't claim to be a professional mechanic but I've wrenched on motors my whole life. I believe the motor has a stator, regulator charging system so I can't figure out how it is overcharging. The old 2 stokes sometimes had a problem with diodes or bad connections that caused over charging but I've checked all that. The regulator is a hefty 6 wire heat-sinked unit. Hate to think that that the new one was bad out of the box. So, is 14.8 "that" bad? Seems high but the only symptom the boat has is the radio beeping "High Voltage". Would love to get a little input. Thanks for the help!!!!!! AL
 
Thanks papyson. I didn't think that was real bad. Was just wondering what caused the increase in voltage. Do you know of anything I can do to reduce the voltage to my VHF so it won't shut down?
 
what are the specs on the vhf?input voltage range?if possible i would call the manufacturer...what bugs me is the fact that it worked previously...have you done and adding of gauges or instruments to the wiring on this boat?changed the load in any way?if you run with a full load and the voltage is down to 14.5 or so does the alarm still go off?
the overcharging you referred to on some motors happens when you have a rectifier only charging system...then it is unregulated output and with the newer batteries the voltage will go in the 16v or higher range...if you have a regulator you dont have that problem...
if it was my rig i would disconnect everything but the battery...run the engine and see what the voltage is...if its reads 14.8 i would kill the engine and connect the vhf only...if the 14.8 is within the specs called for by the vhf then the problem lies in the vhf....if the specs call for a lower voltage you could add a low ohm hi wattage resistor in the lead from the battery to the vhf...(1 or 2 ohms...i would be guessing as i dont know the load of the vhf)...
post the make and model of the vhf please...we may have someone in here more knowledgeable than i on it...
 
Good advice. I was planning on taking everything off line and giving just the motor and battery a voltage check in the next few days. Have not touched anything electric on the boat lately. If I turn on anything else and get the voltage below 14.7 the radio quits alarming The radio is a West Marine VHF 580 but is actually made by Uniden. So here's a kick in the butt. Called the tech at Uniden and he said all Uniden and West marine radios will alarm at 14.3?????? The ops manual say 10.9v to 16v is the operating range the radio will function in but the alarm is set a 14.3. OK so I'm no electronics tech but most outboards, 2 or 4 stoke, should charge better than 14.3 running correct? I've got other boats with radios and another VHF on this boat and never had an alarm at 14.3. He also said that is a preset alarm and cannot be changed. He did not want to hear anything about charging voltage on outboards. I think I have the same model radio on another boat so I'm going to swap the two and see what that does. Asked the guy did I need to tell everyone that had a Uniden radio that didn't alarm at 14.3 to send their radio in for repairs and he hung up on me. Go figure...... I'll keep ya'll posted!!!
 
banged the web a little bit as i am sure you have done before...you are not the only one that experienced this problem....i found no fix though...also found some hits on under voltage alarm at 11.5v ....one guy brought up the point that a low battery just might be when he needed the radio...i have had good experience dealing with west marine..a phone call from them to the manufacturer may get better results than you as an individual making the call...from what i saw on the web on that radio i conclude that there is nothing wrong with your engine charging system..as an after thought i would make sure the ground on that radio is good if it uses one...
 
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