Merc 150 Hi Voltage

[xsportz98]

Hi all, hope someone can help me with a little problem. I took my 1993 150 Merc carby for a run on the weekend and noticed that at <1000rpm the volt meter read 12 volts or there abouts, but as revs increased the gauge went off the dial, followed soon after by a blown 27 meg radio, a loud pop and smoke from my CD player, and Volt, Taco and fuel gauges filling with smoke the amount even varied with throttle position.....more revs, more smoke! I got home and noticed that the battery had no water in it, though am unsure if this has cause the problem, or been a result of the overcharging.<br />I have been told that the cause is EITHER stator or rectifier, but can anybody tell me which one it is? also, the approximate cost to replace? Can anybody also explain why my fuses didn't blow and protect my accessories! Thanks for your time and expertise-xsportz98

 

[WillyBWright]

Re: Merc 150 Hi Voltage

Welcome to iboats and sorry for your misfortune.<br /><br />Stator is working, regulator/rectifier isn't regulating. Been that way for awhile judging by the lack of electrolyte. When there was enough in there the battery must've been taking most of the overload. There are two reg/rects on that mounted on the backside between the coil bracket and exhaust cover. I expect both will need to be replaced. Haven't priced them lately, but they're over $100 US each. Typically they fail and don't charge at all. Kinda rare to overcharge. You probably have one reg/rect that's not charging and one that's overcharging.<br /><br />Now to address why they went bad. The vast majority go bad due to loose and/or corroded battery connections, or from connecting the battery backwards (even for a split-second). No fuses blew because they fail based on amps, not volts. Glass automotive fuses are rated for up to 250 volts. They're putting fusible links on some newer models to prevent this. They're supposed to blow before the regulator does.

 

[xsportz98]

Re: Merc 150 Hi Voltage

Thanks Willy, hopefully I can grab the parts prior to the Holidays.......Happy days!