90hp running on 2 cylinders

90hp has been great until this weekend gone. i had been skiing for about 3hrs when i thought i had run out of fuel whith out checking switched tanks it started straight away i gave full throtle but couldn't plane it wasn't firing on all cylinders.i drained the fuel by idle( i relized 1st tank was not empty ) reconected fuel hose primed and took off on all 3 cylinders after 20 secs same problem occured.i dont think #2 cylinder is getting spark.Is it posible that lead is breaking down? All 3 plugs are good.Or dose this sound like crapy fuel.? All 3 carbies were recondisioned not long ago. thanks heaps for your help..!!

[boats.net]

Yes it could be an ignition or carb problem. Check compression, check vents on fuel tank, check for water in fuel. Try a new set of spark plugs and see if you can tell which cylinders are misfiring.

[jb123]

swap coils to see if that changes anything.

a clogged carb can SEEM like a non-burning cylinder

thanks guys swaped coils and plugs and have spark on all 3 cylinders cleaned tanks and changed feul hose with new primer.im pretty convinced that it may be a choked carb. I have heaps of compression.i had all 3 carbs cleaned and all new needles and seeds replaced resentley is it possible some thing is jammed or sticking.