Mercury 15hp oil/fuel problem
Not my boat, but friend has a Mercury 15hp 4-stroke twin cylinder Big Foot - I don't know the year.
Recently started to cut out at idle but OK at wider throttle openings. Fine before that. Oil level also around 1/2" to 3/4" higher than than it was when he last checked it before this issue. No water in oil & (to my surprise) no particular smell of petrol in the oil or obvious thinning of the oil.
My own suspicions would be a perforated fuel pump diaprhagm, sticky float valve or leaking carb float.
Any known issues with these engines in this department?