Sitting out here waiting for the next sturgeon bite on the St. Croix, so I took a little time pulled apart the dashboard to find out why my tack isn’t working.
There’s four terminals on the back of the tachometer, one is a ground and the other three are supplied 12 V when the switch is in the on position.
Since they’re all getting 12 V is it safe to assume that I need a new tachometer?
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I could be way off but I heard somewhere that it could be the voltage regulator. Mine (2003 125 merc) was acting up and not working at times. A few trips later the motor was in flames.
I hope I’m wrong.
If it’s the same as my 150 if one of the voltage regulators go bad the tach quits ,if you have 2 VR’s check for a grey wire unhook from one hook up other one then if it works you need a new VR
Stan
Thanks guys!
Well after listening to you guys and talking to Redneck, I decided to do a search online and came up with the voltage regulator rectifier seems to go bad on these units and can spontaneously catch on fire’
When I say spontaneously I mean they can be sitting in your garage and start on fire.
I found a site that had a simple test to check out the regulator. Last night when I pulled the cover off and unwrap the wires I found they were all melted together at the connections!!
New regulator should be here tomorrow wires disconnected until then.
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IDO saving lives one rectifier at a time…..
Seriously though that’s pretty dam cool that could’ve done some damage if circstamces were right.
I wish I had heard about it before mine went up in smoke. I had smelled something a week or so before and took the cowling off and saw nothing. A week after that I took the cowling off to put oil in and found this (I will try to post picture)!
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BK, I hope you found through the wonders of the internet that you may want to install a Yamaha rectifier not the unreliable Merc fire starters! The Yamaha was half the price too! I had an issue last year and thankfully caught it early! Voltage spikes when throttled up and on plane on the charge gauge!
$60. bought a new (and improved??) rectifier.
I saw the talk about the Yamaha’s but didn’t go that route.
Had the same problem on my 75 merc this year just before the Salmon GTG. Had my mechanic do it, since I didn’t know what was causing my power loss. Replaced it with a “new and improved” merc voltage regulator and its been working fine for a few months now.
BK, my wires looked exactly like yours when I had my problem. Mechanic said, if I would’ve kept running it, it would’ve caused some severe damage or started on fire as these guys mentioned…. He also replaced all the damaged wires and connections. Not sure if you planned to do that as well.
The damage is confined to the plastic around the connectors. I’ll be looking at them closer when I get the part…and replacing the wiring is on the table.
I love my Merc, but I’m a little disjointed the company didn’t have a recall or at least a Customer Service Bulletin for Merc owners to check this regularly.
I agree, my motor has been really solid for me overall, but a little surprised I never heard anything about this issue until it was almost too late…
When mine went up in flames, I did call mercury to report the problem. They basically told me they would submit the report and if enough issues arose, engineering would get involved.
My guess is that it fell on deaf ears.
I had a second one fail on me and was only noticed because my battery wasn’t charging. My guess is that there was some kind of safety mechanism installed to prevent the short when they fail.
If that’s the only issue with the motor, I’d say it’s still a great motor. Better than having to replace it completely because it seized up.
From my research and talking to a close relative who works at Merc, they know its a problem and ignored it for years. The heat sink on the originals are to small and over time the insulation breaks down and poof- there is smoke and potentially fire. That relative in fact steered me to the Yamaha replacement as Yamaha had informed Merc of the potential issue as they were building those motors at the time and were having an issue with the same rectifier on their own motors.
I check the condition of the rectifier(visually) every time I check the oil level now.
I check the condition of the rectifier(visually) every time I check the oil level now.
New Habit!
Well to end this thread, I replaced the regulator the other day.
The only connection that didn’t show some sign of heat/charring was the grey tach wire…of all things.
I noticed the metal to metal connections had some corrosion in them so those were cleaned up with a file. Only one connection to the motor needed to be replaced. All the charring was on the regulator side.
Funny that right above the regulator is a fuse. <doah>
Changed the spark plugs while I was back there. Checking my records the last time they were changed was 4 springs ago. They were looking pretty good considering.
Lower end lube is next come November 1st.
Thanks again for all the help. You guys saved me a lot of time since taking out the tach wouldn’t have done many good.
When mine went up in flames, I did call mercury to report the problem. They basically told me they would submit the report and if enough issues arose, engineering would get involved.
My guess is that it fell on deaf ears.
I had a 1 year old 1999 Mercury 100 HP ELPTO 2+2 outboard start on fire on me during a tournament. Damage was extensive to the point that it burned up the motor cowling and a bunch of the wiring on the motor. The voltage regulator was faulty and it took some intervention by my dealership to get Mercury to warranty the repairs as they wanted me to do an insurance claim instead. According to my dealership at the time the issue with the voltage regulators was very well known.
So you’re saying your handy fire extinguisher wasn’t large enough?
It boggles my mind to think they knew about this since 1999 and didn’t contact the owners! I know my motor and phone number is registered with them.
I’ve had really good luck with my 90, but this is not only unacceptable, it kind pisses me off.
It POs every Merc owner that has ever had regulator issues and had their motor go up in smoke!
Other than that my 90 has been reliable as well.
Thanks for your insight as well Art.
BTW after replacing the regulator the tach works very well.
Art, how do you tell the condition of the rectifier visually?
I placed the new and old side by side and the only difference in them is the old one had burnt connectors. I know there is a test for the rectifier, but I hope I don’t have to get my ohm meter out every time I change the oil.
Well, guess what I will now be regularly watching. I have the same ’01 90hp on my Lund.
Might want to check it now Poo. More so the wire connectors. Redneck had his motor burn up just sitting in his garage.
BK, I just look for any discoloration of the wires coming out of the rectifier and at the connections itself. I also keep close watch of my voltage gauge while throttled up,since that is how I first discovered the issue, as well as my tachometer function.
Has anyone had this issue on a replacement regulator?
If this is only present on the original regulator, why not just replace it anyway.
This makes my stomach turn over thinking how much I fish Lake Superior.
Thank goodness I don’t have this boat or motor any more.
checking my 03 90 now……
So you’re saying your handy fire extinguisher wasn’t large enough?
When the voltage regulator starts to sizzle you can’t put the fire out with an extinguisher. Or at least you can’t until you get the battery disconnected. Until you get that accomplished the arching happening in the wiring looks a bit like a welder gone wild. When mine caught fire we immediately hosed it with the extinguisher with little effect. To complicate the matter this happened in a tiller boat which meant the starting battery was located right below the tiller handle under the splash well. Getting that battery disconnected while a fire was burning a couple feet from my head fell firmly in the “no fun” column.
BK, I just look for any discoloration of the wires coming out of the rectifier and at the connections itself. I also keep close watch of my voltage gauge while throttled up,since that is how I first discovered the issue, as well as my tachometer function.
Art, when you say you keep a close watch on your voltage gauge…did you find low voltage?
James, it sounds like that would have been tricky….and a little more then “no fun”.
The old saying “knowledge is power” applies here. I had never heard of the problem until my motor was a melted mess. If we can get the word out and everyone is aware then that is a start to beating this problem. According to the adjuster at my insurance company– it is a known problem with Mercury motors between 1998 and 2004. I know it does not apply to all motors but mine was a 90 horse 2 stroke and it had the problem. My voltage regulator burned up sitting in my garage but I have heard of several cases of the regulator burning up while the motor was running across the lake. I did notice a burnt smell before mine burned up and when I pulled the cowling off everything looked fine. If I had known of the problem at that point that regulator would have been replaced.
I actually had fluctuating voltage at idle and the voltage gauge quickly pegged out on the high range when throttled up.
As Redneck said, I also had smelled that electrical burning smell while the boat was in the garage the night before I discovered the voltage issue. I certainly feel I dodged a bullet catching it when I did.
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