9.9 johnson

L

LOW

Recruit
Joined
Aug 14, 2011
Messages
2
i have a 1976 johnson 9.9 hp manual start 2 cylinder one carb. dual points with a single magnetic unit with 2 wires one leading to each set of points. this moto drops a cylinder or runs on one cylinder at times or most times. i have replaced both sets of points and condensers both coils, wires and spark plugs but still get same results. can the magnetic unit under flywheel fail on only one cylinder?
 
oldcatamount

oldcatamount

Lieutenant Commander
Joined
Apr 4, 2010
Messages
1,740
Re: 9.9 johnson

Try testing the plug wires for continuity and looking for abrasion or cuts in the plug wires. Hook up a timing light and run the motor. This will show you which cylinder is not firing and narrow your search.
 
A

AlTn

Commander
Joined
Mar 9, 2010
Messages
2,813
Re: 9.9 johnson

the driver coil should not provide spark to only one cylinder..it's an either or deal....you may have a bad connection in one of the amphenol plugs, or a bad ground at one of the coils...if the driver coil is beginning to fail it could get intermittent spark, but probably not to the same cylinder each time
 
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