1988 Merc 70hp low idle surging

[mnfisherman]

My motor runs fine at WOT but when I idle down into 'trolling' it stutters, not cutting out but like a surging. Is this a fuel delivery issue or something else?

 

[racerone]

How did it run for you last season ?----Nobody can see , hear or touch your motor.----Surging is usually a fuel issue.----Test run with another tank and hose.-----Have your assistant operate the manual fuel pump when it is surging.----Remember a plugged carburetor can cause serious damage to a 2 stroke motor.----Replaced the water pump impeller every 5 years ?

 

[mnfisherman]

Bought last spring. I'm only the second owner, had the same issue last year. Adjusting the idle helped for awhile.