Ferm,
What should (or can) I do to counteract this? Please tell me I'm not going to have to rebuild at the end of the year.
Paranoid Boat owner,
BigDaddy

Check your fuel lines, make sure they are newer USCG approved hose. Also make sure you have a good fuel water separator filter, and carry at least 2 spare filters. Also check your fuel lines on the engine. I have read that the clear fuel lines will break apart with ethanol fuel. Another are to address is if you have an older V-20(built prior to some time around 90/91), replace your fuel fill and vent lines as they most likely are not E-10 compatible. The POLY tanks are said to be fine, but the aluminum tanks do give issues as the ethanol will clean ALL of the old black crud out of em that has built up over the years(this is where the spare filters come in). Check your filters often and if any crud shows up in your filters keep changing them out until it clears up. You don't want that crud to make it into your engine.

He speaks the truth...take it from me the fuel water filters are your good friend! I just got finished going through the carbs on my '04 outboard.

Yep, keep them fuel filters clean. I change mine 2-3 times a season. Beats cleaning out the carburator. I just changed back to my original rebuilt carb to try to increase my gas milage. I recently ran the Mercarb on my 170 at Oregon inlet with 5 adults and topped out at 42 mph. Burned a little gas but ran great!!
:sun:

CFelton, whatch out for perculation as well, if teh carb gets hot enough, it will boil the gas out of the float bowl, Make sure you use the thick oem type gasket for the carb base when you install it. Mercruiser offered a water cooled fuel line to ease perculation and vapor lock problems on mercarbs. If you can find one, a 2bbl Rochestor off of an old 888 Mercruiser will fix all your carb problems, it takes a little fabrication, but its worth the effort, easier to start, no flooding, idles better, no heat soak problems