So I went in the garage to start up my karts (Rotax max) which I do if they haven’t been used for a couple of weeks. First one fired right up, second one no go. I could see no fuel was flowing in to the carb so I pulled that of to check for a bad float or stuck valve but all was well. Checked pump and nothing wrong there either. Filter is all clear too. Unscrewed the fuel pick up cap and the pick up tube had disintegrated!
Last year I bought a new fuel tank for my Top Kart and it came with the fuel pick up pipe installed so I just hooked it up and all was good until today. I asume the ethanol has attacked to tube to cause this. I’m going to use the yellow (Tygon I think) tube that I use for all of my other fuel lines. Seems strange it would be fitted with tube that doesn’t withstand the ethanol 
Some lower quality line will degrade and disintegrate over time. I had the same thing happen last year. The pick up just fell off the line as the line fell apart in the tank.
It’s the small stuff that usually cost you the race. I replace all the fuel line, bearings, tie-rod ends every season. Throttle cables every month. Regardless of condition. Cheap insurance because even when you think it is good it may be degraded like your pickup tube. Glad you found it before you got to the track.
It’s good insurance for sure! Replacing the throttle cable every month seems extreme but I had one fail on me in a crucial race one time so you are smart to do that.
We usually change the tubes once every two or three months of use, but even if you don’t use it they dry in time