1986 Mercury 115 HP Weak fire

mudkat

Recruit
Joined
Jun 16, 2012
Messages
1
I have a 1986 115 HP L6 Mercury that has very weak fire on 4 of the 6 cylinders.
I have changed the switches and installed a new trigger. I also used a DVM to test the stator and had a reading of 180.
The coils are all good and the 2 good cylinders have excellent spark.
Has this problem plagued anyone else?
 

redjmp

Chief Petty Officer
Joined
Mar 16, 2005
Messages
536
Re: 1986 Mercury 115 HP Weak fire

Ok how do you know it has "weak" spark?
Are you using a spark gap tester set to 7/16"?
Myself I would swap packs to start. > Does the problem follow the pack? >Yes =bad pack.
No> Swap triggers. Does the problem follow the trigger? >Yes= bad trigger.
No> Swap coils. Does the problem follow the coils?>Yes = bad coils.
No> Check and clean all grounds wires and make sure all connections are tight and all brass nuts secure.Test for good ground at each coil.
Coils should read .2 to 1.0 ohms on the primary and 800-1100 on the secondary.
Have a look here:
http://www.cdielectronics.com/downloads/Mercury_DVA.pdf
And here on pages 83-84:
http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true
 
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