Have a 10 year old 20 hp I c twin started last year but doesn't start this year. Cranks over but sputters to get gas, check fuel line to carb, getiing gas to intake, tries to start blows blue smokes out exaust and backfires and stops trying to start. Replaced spark plugs still not starting,cloged carb or something else, replaced fuel filter also.

have a 10 year old 20 hp i c twin started last year but dosent start this year. cranks over but sputters to get gas, check fuel line to carb, getiing gas to intake, tries to start blows blue smokes out exaust and backfires and stops trying to start. replaced spark plugs still not starting,cloged carb or something else, replaced fuel filter also.

Try loosening the fuel filler cap - could be fuel starvation from vacuum in fuel tank.

Hi,
At that age you are likely to need a #393397 fuel pump repair kit. It is housed in a rectangular area ar the fron tof the carb and held together by three small screws with 1/4" heads. Disassemble carefully to see the order of the parts.
Peace,
Clarke