No Spark/Good spark/Intermitent spark 3 cylinder mariner 75hp

[ellie271299]

Hi, hope some one could help me out here. I have a 1990 Mariner 75hp 3 cylinder outboard. The engine has been starting with no problems this year on trailer (boat not been out this year). Started fine Wednesday, tried Thursday but would not start. Have narrowed problem down to electiccs and ignition. have disconnected wiring harness and am starting from a switch direct from engine. I have a good spark on bottom cylinder, no spark on middle cylinder and a very intermitent spark on top cylinder. I have alternated the wiring from switch box to coils, spark will move up and down the coils, so presume they are ok. If I transpose the trigger wires, ie move the second wire to the top, that sparks, if I move the bottom wire on switch box to the top, that will fire the spark, but cannot seem to get a spark from second/third wires/cylinder. Could this be a switch box problem?, or what else could it be?, I have limited test equipment, an ohmeter, volt meter but nothing else, any help would be greatly appreciated, many thanks

 

[Laddies]

Re: No Spark/Good spark/Intermitent spark 3 cylinder mariner 75hp

Yes, it sounds like a switch box, you can't test the box with a OHM meter but you can test the stator and trigger and if they test good the box is bad so here's the test.

 

[mastrofury]

Re: No Spark/Good spark/Intermitent spark 3 cylinder mariner 75hp

Sounds more like the trigger to me. Sounds alot like what mine was doing. I had spark on top and middle no spark bottom. ohmn your trigger sounds like only one pick-up is hitting..

 

[ellie271299]

Re: No Spark/Good spark/Intermitent spark 3 cylinder mariner 75hp

Yes thought it might be the trigger, but I have swapped the trigger leads around, ie it fires on the bottom cylinder, which is the top wire on the switch box, when I swap around the top and second wire, ie the middle cylinder that was getting no spark, I do get a spark. It looks to me as if the trigger is being triggered, unless you know different, any help greatly appreciated.