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No spark #2,3 & 4 on 75hp, 1986

L

leachy

Contributing Member
Hi All,

Im new to these older larger outboards but looking for advice. I purchased a Glastron V156 as a bit of a project. It was fitted with a 1986 75HP Merc in good condition. Started straight away from cold stopped and started a few times no issues, idled perfect. Towed it about 600miles (1000kms) home no issues smooth roads.

Went to start it at home a few weeks later and some how it has lost spark on cylinders 2,3 & 4. I assumed it was the trigger plate as when I took the flywheel off one of the wires had been replaced.

Still no spark. I have done the following

1. - swapped the wires on the low voltage side of the coil and spark will move with that so no coil issue.
2. - Moved the cylinder one wire to position 2 on the switch box and the spark moved to cylinder 2.

I will be checking the resistance on the stator tonight but if that has gone "belly up" wouldn't I loos spark on all 4 cylinders. Also can stators just go like that, or is there another issue which could cause that.

Thanks in advance.
Leachy
 
I have replaced the trigger plate and checked that the #2 trigger wire creates spark on the #1 spark when the wires are switch at the switch box.

I managed to check the stator I think correctly as described by disconnecting all the wires and checking the resistance. It seems that the blue to blue/white is correct but the red to red/white is more than double what is should be. spec is 56-76 ohms and Im measuring 146 ohms.

Strange how these things with no moving parts just stop working from one day to the next with only being towed home.

Regards
Leachy
 
faztbullet said:
If you have spark stator is working....either trigger is not telling switchbox to fire or switchbox is bad.
Click to expand...

Thanks Fatzbullet, The confusing part is that I replaced the trigger as they had cut and joined a wire for some reason in the past, but if I moved the trigger wire from #1 to #2 location on the switch box there would be spark at #2 cylinder. That made me think the switch box was OK. The reading on the Red to Red / Red White off the stator is 146 Ohms and the spec should be between 56 - 76 Ohms, so Im assuming there is an issue at the stator. I have no idea how the internals of the switch box work, but Im guessing that something isn't getting triggered. im not sure how the four wires coming off the stator interact with the switch box when thing are running.

Thanks for your input I will do further testing.
 
The stator is merely a generator of electricity. It either makes juice or not.

You have another bad trigger coil.

Jeff
 
Thanks all for you help and advice.

Turns out it was the Swithbox, you were right Fatzbullet. What was surprising is the Mercury Service Manual is wrong for one of the stator resistance readings. Red, Read/white says 56 - 76 ohms but I was reading 146 ohms. This was leading me to think the stator was somehow effecting the operation of the switch box.

I found someone selling a used worn out non repairable motor for $100. Came with a very good SS 17P quicksilver prop, switchbox, stator and a lot of other good parts. Swapped out the switch box and started first turn of the key.

Very happy with the out come. The motor came with a complete engine cover so might get it painted up as a period red band motor.

Thanks Again
Leachy
 
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