1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally.

[lazyworm]

Dear All,
I have a 1984 Mercury outboard 50HP. Was working couple weeks ago. Somehow, after the last start, the motor is not fire. Checked no voltage to all 4 coils from the switch box. Seems to be the switch box. But one of the wire from the stator to the switch box and two wires from strigger to the SOLENOID are corroded badly. Is there an immediate need to replace them? Besides, how can I confirm the trigger and stator are working right?

For the corroded wire on stator and trigger, can I just take it out and replace it with a new wire? Would it be very difficult to do except removing the flywheel?

I see some readings from the stator, the red gives around 15V and green one gives more than 1000V. Are they normal?

Another question is whether the switch box model # 332-5772A1 compatible with 332-5772A7 for 1984 Mercury outboard 50HP 2-stroke 4 cyclinder?

Thanks in advance.

 

[JUSTINTIME]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

u need a dva and meter to test stator
u can use ohms but it is only good for insulation breakdown test

 

[lazyworm]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

I replaced the stator and trigger. I get the following reading which seems to be low based on info I found on other website.
Stator: New Stator Old Stator
Blue: 68V 0.1V
Red: 9.8V 0V

Trigger (New)
Black: 0.1V
Brown: 0.1V
White 0.6V
Violet: 0.1v

Since both stator and trigger are new. I am expecting a good reading, but seems to be not. Any Idea or help?

I also see a little reading from the kill wire (yellow/black) not showing everytime
1.1V AC or 0.2V DC.

Appreciate for any help.

 

[verado7]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

disconnect the stator wires from the switchbox and read the voltage when cranking the engine - if it goes up to normal you have a bad switchbox - do the same for the trigger -if voltage is normal at cranking -switchbox is bad .

by the way i think what you have is a "clasic fifty" it is 45hp - and yes the the switchbox is right those are just old numbers . i own a 1988 .

if you are getting voltage on the kill wire when it is disconnected - that voltage will kill the switchbox - i dont use the key switch anymore for shutdown - i run a wire from the switchbox to a seperate kill button for just that reason .

 

[lazyworm]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

Thanks for the tips. Wonder what should the voltage be for the kill wire. I saw some saying should be 0V all time. Some say 100V all time. Which one is right. Another problem is I get a new rectifier and it get burn after a few crank. I checked there is no continuity between the yellow and ground, but it was before cranking. What did I do wrong?
I also checked the resistance on the coil. The resistance was dropping from high to low. Then show discontinuity. Repeated the dropping when I retest again. Is it mean the coil is bad too?
Thanks in advance.

 

[verado7]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

the kill terminal on the switchbox will read high voltage - but with the wire disconnected , you dont want to see any voltage on the wire itself when the keyswitch is turned on - that wire is a ground to kill the ignition .

-the rectifier burning is likely the stator - and just so you know - a bad switchbox can and will take out the stator in just seconds - the voltage of a bad box can backfeed to the stator ( 180volts plus) not good .
-there should not be any continuity to ground from the stator on the yellow wires at any time .

-as ageneral rule it is always best to replace the stator and switchbox together at the same time for the reason stated above .and your description leads me to think you replaced a stator on a bad switchbox . not what you want to hear i'm sure .

 

[lazyworm]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

[-the rectifier burning is likely the stator - and just so you know - a bad switchbox can and will take out the stator in just seconds - the voltage of a bad box can backfeed to the stator ( 180volts plus) not good .
-there should not be any continuity to ground from the stator on the yellow wires at any time .]
I don't see the continuity from yellow to ground. I don't see voltage from the stator if I disconnected it from the switchbox. Does it mean I blowed it? I took it to a mechanic and he said the problem is the stator. But he didn't mention the switchbox is bad. How can I confirm the switchbox is bad? Based on the voltage, is my stator, trigger and rectifier are all gone? Is it I have to replace all again, would my warranty cover for it? I think I had made a big mistake.

 

[lazyworm]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

Besides, I see some switchbox on ebay. Are they reliable? If I changed the switchbox, would my stator work? Could I also destroyed the coil too?

Thanks in advance.

 

[verado7]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

no voltage from stator means bad stator - given the shorting you have had with the rectifier and what not - i personally would replace the stator,switchbox,trigger and coils - but thats up to you - think of it this way -the ignition is over 20 years old - a few hundred bucks to renew it it is alot cheaper than a new motor - i recently did the same to mine since i was replacing a 20 year old stator it just makes sense to replace the rest as it was all 20 years old . now if soemthing went wrong in the next 5 years or so i would test each part .

 

[lazyworm]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

Wonder if I get a new switchbox only would the new, but broken stator damage the switchbox? I am still not sure the stator already got or not since I didn't connect the yellow wire to the rectifier because the recitifer is dead too.
With you commend, I may destroyed my new stator, trigger and rectifier. Am I correct? Or you recommend to get all at once?

 

[verado7]

Re: 1984 Mercury outboard 50HP not starting and no spark on 4 cyclinder occassionally

get everything at once - even though usually the switchbox damages the stator - the same could happen in reverse - however your postings tell me the stator is no good - dont chance it .