90HP Mercury 4-Stroke Carburator problems.

[Sabs28]

Have a 2005 Mercury 90HP 4-Stroke with 4 carbs & electric choke. Last couple of seasons I noticed the motor only starts if I feather the throttle & runs like a cold blooded 4-stroke until it warms up. Has a "misfire" that gets less & less as the motor warms up but always has a misfire. Misfire is always around 2500-2700 rpm. Have tried all sorts of fuel additives/ cleaners, Marvel Mystery Oil. Have put new spark plugs in it every spring with no change in improvement. The local dealer tells me the carbs get all clogged up because of the Ethanol in the fuel. Any one else have the same problem?? Any info would be helpful.

Thanks..

[Chaps]

Yup, common complaint. Take the carbs off, disassemble, soak in cleaner, blow out all the tiny jets and passages, watch for corrosion especially around the float bowl needle valve, etc. Figure on doing this every couple of years.