1999 Mercury 115 surges back & forth?

[Dean]

I have a 1999 Mercury 115 that surges back & forth from 2200 RPM through 4800 RPM. It is a 4cylinder 4 carb motor. Great compression,new fuel pump,carbs are rebuilt,new trigger & rectifier. Reeds look great. Stator & all 4 coils appear to be perfect. The motor runs great at idle & at wide open throttle. Overall the motor looks new. Could I still have a bad stator Or a bad coil even though they test & function fantastic. I'm stumped on this one. Any suggestions???? Please email me.

[JUST-IN-TIME]

Whats the serial number please

[fastback4]

I had a fuel enricher solenoid kick in and out on my 1999 60hp merc. and it was surging too. Replaced the fuel enricher......Tom

[rynonugget]

What is the fuel enricher?

[fastback4]

fuel enricher solenoid

On my 60hp Merc BigFoot the fuel enricher is a electricaly charger valve that when activated by the ignition key switch(pushing in on the key) delivers a large amount of premixed fuel (for a 2 cycle engine) directly into one or more engine cylinders to aid only in cold starts. I have used this accidently after my engine was warmed up and i flooded the motor.

[boatmangc]

How did you verify the stator/coils?
Try a test run with 1 plug wire off at a time and see if you can narrow it down to a cylinder or 2.
If you disconnect a plug wire on a cylinder that isn't doing it's job there will not be a change in performance.
If you disconnect a plug on a working cylinder you will see a difference in performance immediately.