2004 Mercury 60hp blown regulator

desertratz

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Jul 16, 2017
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I purchased this boat not too long ago. Tach never worked and was not charging battery. replaced the voltage regulator and it fixed it for one lake trip. halfway through the day it stopped charging and the tach stopped working. Im assuming it blew the regulator again. what would cause this? this is a 2004 mercury 4 stroke 60hp
 

Texasmark

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Dec 20, 2005
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You could have blown a fuse.....not familiar with 4 stroke wiring, or you overloaded the regulator due to too many amperes being drawn from it for whatever reason, it wasn't heat sunk to a thermally conducting surface adequately for the current being supplied, or your input voltage from your stator was too high. Then there is the possibility of a faulty replacement part.

If the one in the boat wasn't working and the new one quit working, I'd think that you have a load problem in the boat. I'd start with your battery. Have it load checked. If you are running a boom boom box, maybe the wattage rating, and sound level are too high for your engine's capabilities.
 

Faztbullet

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Has the motor had the update done to it???It will have a fuse and different exhaust plate. Part should look like below...
apivjeekt__48355.1534430853.jpg
 

desertratz

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You could have blown a fuse.....not familiar with 4 stroke wiring, or you overloaded the regulator due to too many amperes being drawn from it for whatever reason, it wasn't heat sunk to a thermally conducting surface adequately for the current being supplied, or your input voltage from your stator was too high. Then there is the possibility of a faulty replacement part.

If the one in the boat wasn't working and the new one quit working, I'd think that you have a load problem in the boat. I'd start with your battery. Have it load checked. If you are running a boom boom box, maybe the wattage rating, and sound level are too high for your engine's capabilities.

there are no extra electronics just a fish finder. not even a regular radio. I checked all the fuses and none were blown. my initial thought was the stator was putting out too much juice but i dont have a reliable way to check it. i used a voltmeter at about 3000 rpms judging from sound since the tach is dead and it was reading 70 something volts but i dont have the correct meter to accurately read peak voltages. the replacement part worked great for a few hours so im guessing it wasnt a problem with the part more like something else.
 

desertratz

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Has the motor had the update done to it???It will have a fuse and different exhaust plate. Part should look like below...
apivjeekt__48355.1534430853.jpg

I was not even aware of this update. the plate looks the same but it definitely does not have that inline fuse so im guessing it has not had the update. where can i find more info on this update?
 

desertratz

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still havent been able to figure this out but something i find weird is the regulator only has 3 wires. 2 yellow coming in from the stator and one red coming out to charge the battery. if i unplug the red wire and start it up im getting 13.8 volts here. if i pug it back in and backprobe it im only getting 11.8 volts? so is the stator not putting out enough juice to charge? the stator and regulator both check out via bench test with a voltmeter.
 

Texasmark

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Too much load on the regulator will cause larger than rated internal voltage drops which will over heat it and the supply (stator). The ground for the regulator is apparently the case. Could be that the case does not make good contact back to the battery - terminal. Suggest you clean up mounting screws and such along the metallic conduction path back to the point where the battery - terminal connects to the engine...internal connections where current flows meaning screws and terminals and contact points need to be disassembled, cleaned till shiny and re attached.
 

wn6ngp

Petty Officer 1st Class
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Aug 12, 2012
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209
Have you checked the battery?. If you 1 bad cell it will cause the voltage to drop to a low level and present a heavy load to the charging circuit.
 

desertratz

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update, i wasnt getting a good ground to the regulator case so i repositioned the grounds and swapped the battery with my trolling motor battery which is basically new. the tach is not working but im only reading 12.5 volts at the battery. does the regulator put out a variable voltage depending on battery charge?
 

Texasmark

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Yes and the operator's manual starts taking output data (amperes vs rpms) above 1k rpms for smaller stators like I would assume your engine has. 12.5v on the battery with the engine up around 1500 rpms is no output from the regulator. If you have a known good battery, have cleaned up the grounds, and have replaced the regulator, the only thing left is the stator.

Considering a full wave bridge rectifier (works with 2 floating input connections which is what the stator yellow wires are) in the rect/reg module and the capability to produce 13.5 volts or so up to rated amperage, and 2 diode drops of say 1 volt at high current values, would require an RMS AC voltage input voltage of 15.5v minimum. Considering an unloaded AC source, like would be the case with the output leads open circuited (not connected to the rect/regl.) the voltage could/would be higher.

I never tried this but it should work: Disconnect the yellow leads from the stator and put your DMM on the 20 VAC (not DC) scale and connect to the disconnected stator output wires. Run the engine up around the 1500 rpms area and record the voltage. You don't need any kind of adapter (DVA) for this. This is pure sine wave voltage from a magnetically induced coil of wire.

Post back.
 

desertratz

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took it out this weekend ran good tach is working well. but still getting only 12.5 volts. didnt run it long enough to see if it would drain the battery. but the battery was definitely an issue. the tach will not work with the old battery must have a bad cell. i disconnected the yellow stator wires and have 20 volts at idle and about 60 volts ac at 2000 rpms.
 

Faztbullet

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does the regulator put out a variable voltage depending on battery charge?
Yes..It maintains the battery around 13V..If you turn on all the accessories and lites you should see voltage increase as RPM rises to replace the load being drawn from battery
 

Texasmark

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took it out this weekend ran good tach is working well. but still getting only 12.5 volts. didnt run it long enough to see if it would drain the battery. but the battery was definitely an issue. the tach will not work with the old battery must have a bad cell. i disconnected the yellow stator wires and have 20 volts at idle and about 60 volts ac at 2000 rpms.

Back to the battery.............have it load tested.
 

Texasmark

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3rd trip out without charging the battery so must have been the battery.

I don't understand this comment. You are still not charging your battery. Fully charged 12v battery under STP (Standard Temperature and Pressure) is about 12.75 volts. As Faztbullet said, the output of the regulator will be above that voltage at any RPM above 1000 for a number....as rpm increases output increases from the regulator increases up to a max of 14.5v usually if battery is able to fully charge up to the stator output for that rpm.

Your tach comes off the input to the regulator. Apparently your old battery caused your regulator to over work and damage something in the regulating circuitry. Your tach says the stator and rectifier part of the rectifier/regulator module are functioning.

Get whatever battery you choose to use and take it to wallyworld or autozone or such place and have it load tested. Load testing measures voltage as high current is drawn from the battery. Ensure whatever battery you use has passed the load test and is fully charged after testing.

Measure the voltage at the battery terminals with the engine and any boom box or high current drain accessory turned off. However you choose to do it, get the engine running up around 1500 rpm for a number. Measure the battery terminal voltage again. If the tach is working properly and you aren't getting more voltage at your battery than you initially had, your regulator part of the rectifier/regulator module is not functioning properly and needs replacing. You have already eliminated the stator as a possible problem so don't waste your time going there.
 
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