Spark problem? 1990 Mercury 60

Ilovefishing

Ilovefishing

Cadet
Joined
Aug 9, 2015
Messages
19
1990 Mercury 60 hp Serial# 0C288343. This is driving me crazy. A few weeks ago I was on the lake and boat ran great, then after stopping for a hour or so fishing it didn't want to idle without using the warm up lever and barely get it in gear to move but would only run maybe 10 mph and not well. Initially thought it was a fuel problem so pulled the carbs apart and cleaned them and took it back out with same result. Also replaced plugs at same time so I pulled plugs and noticed #2 hasn't been firing, so checked spark on all 3 cylinders and #2 had zero spark.
So to check if it was plugs I swapped plugs still nothing, then to check coil pack I moved #1 plug wire down to #2 coil pack and got spark so figured it was the wire bad. Bought a plug wire from autozone which same result thought ok maybe it just wont work so fast forward to today, I bought a Mercury plug wire for my motor same one as it came with.
I hooked it up and nothing! I even swapped the #1 plug wire back to the #2 coil pack then that wire to #2 plug firing great, blue arc. So put the new wire into #1 coil pack to #1 plug and had some spark thought now we getting somewhere, tried to start boat and nothing, pulled plug from new wire and its a very faint spark not a bright blue big spark.

Please help, I am Lost. Where should I begin looking? Thanks in advance.
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
CDI Troubleshooting-Guide-Inside-Pages.pdf Clearly spells out how to test to determine what is at fault. You will need a DVA meter or a DVA Adaptor to use with any Voltl/Ohm meter.

You could switch the trigger wires on the switchbox and see if the 'no spark' moves to another cyl. This would indicate a bad trigger. If it stays in the same place it could still be either the switchbox or #2 coil. If this happens simply switch two coils. If the 'no spark' follows the coil then it is pretty clear the coil is bad.

always remember, There is NO RETURN on electrical parts. You must PROVE the fault before ordering any parts.
 
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