1986 Merc 90 Inline 6 - No spark on 1-3-5

[jeff_smith_0423]

Evening gents.

I have a 1986 Mercury Inline 6, 90hp. It was running well until tonight. While pulling away from the ramp it quit and was very hard to get restarted. Got it "sort of" running long enough to get out of the current and back to the dock. Hauled it out and when I got home found no spark on 1-3-5. It started to rain and I didn't get a chance to ohm out the trigger. I do not have a DVA meter (if absolutely necessary I'll slap one of Chris' homemade ones together. If the trigger ohms out properly is it safe to assume that it's a blown switch box ? If so, should I replace both? I'm unsure of the rest of the motor's history other than the oil injection has been removed and it had excellent even compression (140-145 across all six) when I bought it a month or so ago. I've put about four hours on it since i picked it up.

 

[Laddies]

Re: 1986 Merc 90 Inline 6 - No spark on 1-3-5

You either have a bad switch box or one side of the stator has failed, remove the red and blue wires from one box and switch them with the red/white and blue.white from the other box if the problem goes to the even number cyls. it's the stator if it stays the same cyls. it's the box.

 

[jeff_smith_0423]

Re: 1986 Merc 90 Inline 6 - No spark on 1-3-5

Great. I'll get the trigger Ohm'd out and test swapping stator leads tomorrow once this rain quits. Seems like the exact problem I had with another motor.

 

[Chris1956]

Re: 1986 Merc 90 Inline 6 - No spark on 1-3-5

Jeff - Ladies has pointed you to the problem. If you still want to concentrate on the trigger, even though it is good, ohm away!

 

[jeff_smith_0423]

Re: 1986 Merc 90 Inline 6 - No spark on 1-3-5

I'm sure it's good, too. But, since i'm in there and i've got it all apart, no reason not to check everything else. Hate to blow another switchbox if there is another problem in the chain.