Engine Misfiring

[aturner]

Lately my 05 ETEC 50HP will not fire on one cylinder after running at speed for a modest period. I found if I idle the engine for a short period, it clears up but will misfire again on one cylinder once I'm back underway. If I keep the RPM at 2000 or less, it runs fine. Bought new plugs, will install tomorrow. My question(s): are we getting too much alcohol in our fuel these days? Should one be putting addditive in fuel to help this situation and if so, what type/brand? Then there's the age old problem of finding a decent marine mechanic anymore to ask a question or even get to work on ones engine. It appears shade tree mechanics are everywhere and ripping owners badly. Doesn't this industry monitor such dealerships/repair shops to ensure quality workmanship or are we just fair game?

[aturner]

New plugs cured my problem.

[boats.net]

Unfortunately the Ethenol is play heck with the fuel systems in the marine industy. Startron is a good additive also stabil. Spark plugs should help if problem persist have a computer download completed. If no codes chances are fuel issue.