Couple notes on small motors and ethanol. First corn belongs on the cob not our petroleum! Second anything remotely resembling ethanol belongs over ice and served by the shot. Lastly ethanol is one wicked cleaner/solvent. (old racing fuel cells would melt when ethanol was introduced) With that out of the way. If you have confirmed you have ethanol in your fuel and it's old and untreated... dispose of it properly. I had a problem with ethanol on a 2008 Yamaha 4 stroke F40 carbed outboard. In less than 30 hours of use on a BRAN NEW motor on a BRAND NEW skiff. All three carbs were replaced at least once. Ethanol basically crystallized on the idle jets. Much like a grain of sand in an oyster the ethanol pearl would grow to the point that the motor would refuse to start. Nothing like trying to start a 4 stroke 6am in the summer in Flamingo while being drained of your blood by all the skeeters! Yamaha did help out and covered the replacements under warranty. I have since spoken to a few reps at Yamaha and out in the field. There are a few other solutions that include a specialized ultrasonic parts cleaner to soaks in MEK overnight. (as mentioned above) The issue is that you might solve the problem for the short term but it will rear it's ugly head again unless you treat the source of the problem, ethanol. Every manufacture I have talked to while conducting a recent Four Stroke Shootout on my site all chanted the same tune. Treat your ethanol and use a 10 micron fuel filter, no exceptions! There are several options out there. Some are a bit OVER stating what they can do IMHO, but since we started treating the fuel, NEVER leave the tank less than full and run a religious regiment of checking and replacing our 10 micron filter, the problem has not returned. Coincidence? Not likely. I can tell you that many mechanics are just as stumped as we are with regards to ethanol. The manufactures are working hard to get everyone up to speed, but in the end we have to take the due diligence to research on our own and learn from our shared experiences. Cheers Capt. Jan