I doubt that "water in the pipe" is the cause.
It could be anything!
Two weeks ago, my motor just quit running. I was lucky I was close to home.
I took apart the carb and replaced the jet with a smaller size. Cleaned it all up and checked for good fuel flow. All that checked out. Still nothing.
Checked all my connections. Unhooked the kill cable connections. Put in a new NGK spark plug. Checked for spark after the sun went down. A little something but not enough. Bike still wouldn't fire. Not a single pop.
Two weeks later, I put on a new CDI with a new, upgraded plug wire. Still no go!
I replaced the coil with one I know is good. Checked the plug for spark and as I was holding the plug against the engine case, that thing lit me up! Replaced the spark plug and made sure it was attached to the plug properly.
Still no start after a few more tries. I was getting tired from the pedalling!
I decided to look at the new plug. I KNOW I have spark. Carby is clean. I looked at the new plug. It was dry. I opened up the needle valve on my fuel line and pedalled about 50 yards on a soft, downhill slope. Bam! it kicked and started to go. A little sputtering for a few hundred yards then ZOOOOOOM! The thing took off and I was flying! No four stroking, just good power and speed. it is like a new bike!
The lesson here is never give up! The first problem was probably an failing coil. The second problem was very little fuel in the float bowl after two weeks of no riding.
Check everything!