Mercruiser 8.1 RPM oscillations at cruise

[R-and-R]

2nd cruise of the season.

At cruise speed, about 3400 RPM, my starboard engine intermittently drops 200-300 RPM for about 10-15 seconds, then recovers. Does this very 2-3 minutes. Fuel flow and other indications stay steady, but definite noticeable power loss.

Thoughts?
I’m leaning towards spark plugs and/or fuel injectors.

 

[lawndoctor]

Consider replacing the spark plug wires. Sometimes the 8.1s fry the wires. I replaced all of mine. They are not cheap. There is a long thread on here somewhere about sourcing the wires for the 8.1s.

 

[R-and-R]

Consider replacing the spark plug wires. Sometimes the 8.1s fry the wires. I replaced all of mine. They are not cheap. There is a long thread on here somewhere about sourcing the wires for the 8.1s.

Wires, plugs and injector cleaning were all in my plan for end of season. May have to bump up my timeline.