Electrical problem...please help!!!

Alright, I apologize in advance for the long post, but I think if you have all the details, you might be better suited to help me out, so here it goes....

A couple of weeks ago my new "stock" battery was dying on me leaving me dead in the water. I should have seen it coming as the last few years my alternator has been week...voltmeter only reading 10-11 volts while at wakeboard speed but I never really had a problem until this year. I decided to pull the alternator and have it tested...of course it was dead, so I took it to have it rebuilt. whala...my stock 37 amp alternator (I have an 83 sn2001 w/351) was re-wound to 55 amp.

I put it in the boat, and at first I was getting a reading of 12+ volts, then kinda stopped looking at the voltmeter and again and then next time I looked it was at 10 volts wakeboard speed and like an idiot I shut the boat down when the boarding set was done and I was stranded dead in the water (luckily only a 10 minute swim from the landing). Called the guy who re-did my alternator and took it back... As it turns out, the voltage regulator on the back of the alternator went bad or was bad from the start. We ordered a new voltage reg and put it on.

Just got the boat back all ready to go today for the fourth and fireworks tonight, so I put it in, start it on the trailer, and idle away. all is well. voltmeter reading 13-14 volts just as I am gettin up to plane and then the engine sputters, my tach needle pins above 6000 (the rpms dont change though) and is smoking, voltmeter jumps to 16 + and my temp gauge skyrockets. I immediately idle down and open the engine cover just to check engine temp and it is not that hot...must have had a power surge or something. Either way, I idled back to the landing, put it back on the trailer and went to shut it down. After I shut it down,I HAVE NO POWER TO ANYTHING. Nothing to the accessories, ignition switch, lights, etc. I checked the main breaker and it did not pop. Lucky I didn't shut down in the middle of the lake otherwise I'd have been dead in the water yet again.

I am getting really frustrated with this cause just when I think I can fix my alternator, it turns into much larger problems. What do you guys suspect happened? What is wrong with my boat? Did my voltage regulator give out in the open position if there is such a thing?? I am going to check the continuity of the alternator/battery hots and grounds tomorrow and see what I can deduce from that, but do you have any other suggestions? I am fairly mechanically inclined, but know little about electrical systems. I appreciate any advice you can give! Thank you!! I really don't want to re-do the gauges at this point in time, but might have to slowly after what happened to the tach.

Kyle

Kylem, I can think of two things that could cause your voltmeter to read 16+ volts. They are: a bad voltmeter and a bad voltage regulator. Since you have multiple symptoms, high voltage from the alternator caused by a bad regulator is the most likely culprit. This will cause all of the other gauges to read incorrecly and can eventually cook your battery and as well as other things. You said the voltage regulator was on the "back" of the alternator. Did you mean it is external? If so, I would replace the alternator and voltage regulator with a newer type alternator with an internal regulator. My favorite is the GM 10SI or 12SI.

Since you lost power to everything, like Skibum said above, you need to troubleshoot that problem as well. It sounds as though you may have blown a main fuse somewhere,....possibly feeding your ignition switch on the B+ side. Good luck! Please get back to us with your findings. Brian

Chris, a lot of the stock units were Motorola alt. rated at 35 amps and came both ways.It really is not an internal regulator more like integral, it bolts to the brush housing on the rear.
As far as the regulator it is the same, the difference being in the stator,and rotor .The rectifier diode assy. being the same.
But agree with the 10SI one wire upgrade, thats the only way to fly.Just upgrade the battery wire from the alternater to the solenoid to a big fat wire and your set......boat dr

you didnt specify the condition of your battery...I ran into this problem last week, no juice from altenator,pulled it had it rebuilt put it back in and was reading 16 volts, customer insisted battery was new last year. pulled battery and sides were buldging which is a indication of overcharging. installed a known good battery and volt meter read normal, hope this helps

well Jim you don't have to change the rotor or have it rewound or have more mass, you do have to rewind the stator doesn't have to be heavier gauge wire or more of the same gauge wire just more turns, most stators have over sized slots to start with so adding more turns and wire isn't an issue at all and is pretty common in the industry it's all in how the fields are wound and placed in the stator that determines the output. Grated there are limits and if the lamination's slot and mass are already maxed then you have issue, but if you compare a GM alternator with a 100 amp output to a 85 amp unit the stator laminations are exactly the same as well as the rotors too. So it us not unreasonable that a 35 amp unit is switched to a 55 amp unit.

Don't get me started Chris.

No you don't, to change a 35 amp motorola to a 55 amp all that is required is to change the stator. same goes for a 10SI GM , to go from a 35 to a 55 simply change the stator.
All this changes at 65 to 100 amps . Rotor stator and rectifier bridge all have to be changed,the voltage regulator stays the same.
Sorry guys ran an alternater shop for 5 yrs,chris have to disagree about the motorola thing, not as good as GM ,but better than Bosche or Lucas.Would put Leece/Neville at the top of the list......boat dr

I think the guy wasted his money and should have bought the upgrade from SKIDIM.

the boat i was working on showed a true 16 volts with a dvm, i pulled the battery and installed a new one and it came right down to 13.5, At first the rebuilder told me the adjustable regulator needed to be adjusted (under the cover is a screw for adjustment) I went with the new battery and the problem was solved

it would have cost under 300 bucks from skidim

its a plug and play type deal. All you had to do was unplug it at the back of the motor, disconnect all of the wires and then reconnect the new harness up pretty easy and strait forward, oh well.