Greetings all, new member here and a long time lurker.
I have recently purchased a 2017 Mako skiff with a 60 Mercury four stroke. The engine has a little over 60 hours on it and runs/starts great except for an occasional miss at cruising speed. At around 4K rpm I get a miss that is just momentary. The engine runs smoothly for 10-15 seconds and then there's a miss and then runs smooth again. I've tried different fuel, injector cleaner and higher octane fuel. I typically run 90 ethanol free. Any ideas as what to look for? I've not had it to a dealer yet, trying to avoid that cost.

Inspect and or replace the spark plugs. Make sure they have the proper gap.


If the plugs check out. Spark plug wires.


If the wires check out. Test the coil(s).


If all of those check out. Ignition module.

Thanks for the quick reply! I'll give those suggestions a try, much appreciated!

Just a recap on my engine missing dilemma: I put in new plugs and checked the resistance on the wires and coils and they were within spec. I had to wait for decent weather for a test ride but I finally got it out yesterday. The engine runs great, no miss and smoother than before. I didn't think new plugs on an engine with such low hours would make a difference but it did. Thanks for posting Grasshopperglock!!