Do ignition coils wear out, but still work?

[Old Navy]

My boat had a problem a couple weeks ago, where It would die out at high RPMS and as soon as you pull back the stick a little it would run fine, It was an intermittant problem. Fuel pressure was fine. I really didn't have any symptoms jump out at me, so I bought a new Mercruiser coil and installed it. I can't duplicate the problem now, was that it? Seems odd to have a coil that works but doesn't if you know what I mean.

 

[Mr. Buss]

i have seem some coils do weird stuff when they get warmed up, then have some high rpm issues..

if it worked run with it..

 

[Will30]

In older cars a coil would mess up and not be able to fire enough to start the engine . But you could unbolt the distributor and advance it enough to get it to start then turn it back and the car would idle fine . Electronics do strange things when they mess up .

 

[mkhammer]

Sometimes an ignition coil is bad, clearly bad, as in it makes no spark at all. But if a coil is on the way out, but not dead yet, it can make a weak spark that can cause the boat to run rough or wrong. By testing an ignition coil with a multimeter while it's disconnected, you can determine if the coil is bad or not. parameter should test out between 0.05 to 0.6 on your multimeter. SO a bad coil may operate until it heats up and then sign off until it cools down again. That should shed some light on the situation you had.

mkhammer