40 hp mariner dropping cylinder

DK_BOE_SR

Recruit
Joined
Mar 23, 2009
Messages
4
Hi all
40hp Mariner drops cylinder when run about .5 hr. or so. Has been sitting for about 3 yrs. while working in another state. new fuel tank, new fuel hose, new water pump. Motor runs fine on hose and in water until it drops cylinder. Once run for a while, will not come back on throttle. It just seems and sounds like it is bogging. fuel bubble is hard and no difference when pumped. can idle for a while and when throttled up sometimes will catch after stuttering a while. Can the coil be heating up and failing on one cylinder? Engine has one coil and fires both plugs at once. 40 hp mariner, 40E 676BS105101. Any ideas appreciated.
Dave
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
dk_boe_sr :welcome: to iboats. Nice having you aboard...

When your engine drops a cylinder, do you actually know which one is dropped? If so, swap the spark plug wires and see if the dropped cylinder changes positions. If so, buy a new coil, if not, the ignition isn't the problem... JMHO!
 
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