2 out of 4 spark plugs not firing.

[felderlostnspace]

thanks in advance for any and all help.i have a 78 mercury 80 hp model 800 4 cylinder outboard.the bottom 2 plugs are not firing.i have checked the plug wires from the coils and have checked the coils.all ok.where do i go now besides the repair shop,due to having noo money that is out of the question.does the switch box supply the power to the coils?does the trigger have anything to do with it?thanks again for any help.see ya' Bill

 

[ricksrster]

Re: 2 out of 4 spark plugs not firing.

Check your trigger Ohms. Disconnect the Brown and the White/black. The resisstance betwenn the wires should read 800 - 1400 Ohms. Do the same with the White and Purple wires. The reading should be the same, 800 - 1400 Ohms. If you have a DVA, the DVA voltage between the Brown and Whitee/Black and between the White and Purple should be 4v+.

 

[felderlostnspace]

Re: 2 out of 4 spark plugs not firing.

Thanks Rick.i'll try and check it sometime this weekend.i'll let you know what i find.thanks Bill

 

[felderlostnspace]

Re: 2 out of 4 spark plugs not firing.

Rick,this afternoon i was able to look at the motor.while moving the wires from the trigger to the switch box one of the wires came out of the harness where it had corroided and had broken at the trigger,soooooo i guess i'll replace the trigger and see what happens.thanks for the help.wiring is such a hard thing to trace out sometimes.see ya', i'll let you know what happens.