mercury electrical problem

[renoduckman]

I have a 1988 80 hp 3 cylinder mercury. I have a miss on the lower cylinder that comes and goes. I changed the rectifier becasue i was not getting any charging. The system is now charging but the miss is still there. Also, it seem im getting 16 volts or more out of my system now. That voltage seems to high? It appears this motor has no voltage regulator. I can not find the specs any place that show what voltage this motor will put out? I have a manuel and good ohm meter. I suspect the stator but it seemed to ohm out ok. If anybody has any advice on the problems and the voltage output i will appreciate it. I am an electrician but not a outboard guru! Thanks joe

 

[Laddies]

Re: mercury electrical problem

The alt. system is unregulted so the volts are about normal, the ign problem is probably the switch box and for that kind of a problem you will need a DVA to test for output

 

[Motor Boater Bill]

Re: mercury electrical problem

You can try swapping coils and see if your miss moves to another cylinder with the coil. If so, replace the coil. If not, then you have eliminated that possibility.

 

[renoduckman]

Re: mercury electrical problem

Thanks for the help men. I swaped the coils and its still on the same cylinder. It comes and goes. I thought i had found the problem when i found a wire with cracked insulation on the trigger common wire to the switch box. But that still didnt help the problme and the trigger ohms out ok. Im leaning toward the switch box but was still hopeing to test more. I dont have a dva but am looking for one to borrow. I have been told that the stator can cause these odd problems too? Any more advice thanks joe

 

[Motor Boater Bill]

Re: mercury electrical problem

Since the stator usually charges the circuitry for all the cylinders, it would not seem likely that a fault there would affect just one cylinder, and always the same cylinder, although others may correct me on this. I don't have experiendce with 3 cylinder motors, so take that with a grain of salt unless Laddies or others can confirm it.

 

[MercFan]

Re: mercury electrical problem

To tame my high charge voltage I was adviced to add a second battery or just replace mine with a bigger Ah one. Works like a charm!

 

[renoduckman]

Re: mercury electrical problem

Thanks again for the advice. Im going to add a second battery so thats a good idea. MY electrical skills are rusty now but im borrowing a Fluke that has peak reading abilities. I understand this to be the same as Dva? Has anybody actually tried testing there own switch box ? Thanks Joe

 

[eli_lilly]

Re: mercury electrical problem

The peak isn't the same as the DVA. You can test the switchboxes without a DVA by shorting certain wires to certain points, search for an old post from Clams Canino on how to do this. The switchboxes are also usually pretty cheap on ebay.

 

[renoduckman]

Re: mercury electrical problem

Thanks, still getting my butt kicked. Changed the trigger wires to see if the problem moved to another cylinder and then all 3 cylinders start working! The problme comes and goes. I tryed using the peak meter and im getting ac voltage, not dc. Not sure what im supposed to be getting but i have to try to make it fail again. Im leaning toward just changing the switch box. I dont see a bad wire anyplace. Thanks

 

[renoduckman]

Re: mercury electrical problem

Thanks for the help. While testing with the high dollar fluke for peak voltage, it seems that the trigger is ok and the stator is ok. I replaced switch box and it seems to be working. Ran the motor for half hour on the flushing device and it seemed to be good. I will take it out this weekend and run it and see what happens. Thanks for all the help men

 

[renoduckman]

Re: mercury electrical problem

Well the new switchbox seems to be it. ran great this weekend.