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Mercury 1989 2 stroke 3-cylinder 60 hp voltage regulator rectifier burns out constantly but slowly

K

KUHA96

New member
Hello guys!

I have a problem with my Mercury outboard. I can run the motor for couple trips first well but starting the motor goes every time a little bit worse and eventually no spark at all. When I replace the voltage regulator rectifier, the spark comes back and starting up without no problem. So the big question is what can cause this? And why it have affect on spark? I was having the knowledge that it only acts with AC -> DC for charging battery so why so huge affect on spark as well? I have added heat sink, replaced the battery for non- maintance free battery as the manufacturer recommends, checked the wiring as well the ground.

Any help and tips about how the system works would be really appreciated! :)
 
Here is the component what I'm talking about.

regulator rectifier.jpg
 
When these fail they can cause the stator to overheat and shutdown. Need to make sure ignition plate is grounded, cable connections are tight, if it has a battery selector switch that all connections are secur and not switched while running
 
Understand. Only bizarre thing is that when the rectifier regulator is replaced, everything works fine for while until the sparks start to disappear slowly. So stator cant be permanently damaged if the rectifier replacement fixes the problem. I have checked the grounding as well. I was told that Mercury have type defect in this motors that the trigger wiring goes bad due the constant movement with throttle lever. For me it seems to be ok, must double check though. Any other ideas are welcome too, thank you!
 
Does somebody have any knowledge about the wiring diagram inside the regulator rectifier as in picture? I was planning to build own with stronger diodes and resistors to maybe bypass the problem if I can't solve it otherwise.
 
I was also thinking that maybe the wiring is connected wrong to regulator rectifier. Does anybody have picture how they should be connected? I have 2 yellow ones coming from stator to upper 2 connections and 2 red wires going to lower pin, so 3 connection points...
 
When the spark finally dies is the battery flat? just wondering if there is no charging happening from the beginning and its all created by the battery to run the engine.
 
In theory there is no connection between the stator winding for the spark and the regulator....
My '86 had failing insulation on the stator wires under the flywheel. The insulation was crumbling off, it was not fixable with shrink tube or other methods. I replaced the stator and have not had a problem since...

If you are going to pull the flywheel, buy a speciality puller. It is worth every penny... Good luck
 
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