1998-2000 Yamaha WaveRunner GP800 Factory Service Manual, Page 52Get this manual
SERVICE POINTS
Check valve inspection 1Check: Check valve Faulty -7 ReplaceChecking steps: Connect hose to the end of check valve "A" and blow into itAir should come out from end "B" Connect the hose to the end of check valve "B" and blow into itAir should not come out from end "A"Fuel level switch inspection Refer to "INDICATION SYSTEM" in chapter 7Fuel tank inspection 1Inspect: Fuel tank Cracksdamage Pipe joint inspection 1Inspect: Pipe Contaminants -7 CleanBendsdamage -7 Replace-7