x2 Carb issue. I rebuilt mine even though it was a bit more involved and finicky than I would usually go through on an engine. Got great advice on the marineengine.com forum, and got cheap parts through boats.net. Way cheaper than dealer even with shipping. Was easier than I thought it would be and I had fun doing it. Can't say enough about the advice I got on marineengine, some great guys who were generous with their time. Also downloaded the SHOP manual as a PDF for about $7, compared to $50 the dealer wanted for the paper copy. Just make sure you get the dealer or helm manuals, NOT seloc or others. Everyone on forum said they were either missing stuff or plain wrong.
Good luck!
To avoid carb issues, fresh gas with stabilizer if your not going to use it quick. Clean your water seperator regularly if you have one, ensure no water in fuel if built in tank (condensation can do it), and probably most important, use the drain screw on your carb to get ALL the fuel out if it's going to sit for longer than a few days. Even removing fuel line and running engine dead won't get all the fuel out like draining it. That fuel sits in there and varnishes the tiny ports and jets gumming it up until, well, you know.
Could be another issue too I guess, search that forum for all the other guys who have had similar problems and you'll find the possible causes for sure.