2017 115Mercury Ct

[vintagestar]

My 2017 115Ct Mercury outboard runs fine for 30 minutes then begins to spit and sputter. If I open it up, above 2200 rpm, it goes, da-ga, da-ga, da-ga. I have tuned it up, changed all the filters, changed the fuel even called it bad names. But the problem still exists. I suspect one or both coils are acting up. Or could it be the fuel supply pump modules? Anyone else have this issue?

 

[Texasmark]

If its the fuel pump, squeezing the bulb when it acts up and it recovering exposes that as the problem. If the fuel tank isn't venting, removing the fill cap will identify that.

On spark, coils are usually the culprit when they get hot if they are defective. You can run the engine to get it warmed up and then go to your 2200 and run it there for a couple of minutes or so and while its still acting up, shut it off and pull the spark plugs. A dry plug is the coil is working (assuming fuel is adequately available). If you have a wet plug you either have a bad plug or a coil going south on you.

Not familiar with a 2017 but my 2002 115 2 stroker has individual coil packs per cylinder. If you have individual coil packs, move the pack from the wet plug to the dry plug...high voltage lead and power connector, dry your plug in that cylinder and run it again. When it starts acting up check the plug where the suspect coil pack was connected. If its wet now instead of dry, your problem is that pack.

The other thing you can do with the coil packs is check the spark. I forget the gap and color of the spark required on the test instrument to determine if an ignition system is up to par.

Not necessarily the coil on the individual coil packs. I had a transistor in one of mine once that was thermally sensitive and it would act up when the engine got up to temp......but silicon is usually not the problem....IMO.