30hp 1989 yamaha firing problems?

[sambrigman]

this motor starts rite up runs perfect until i take off, runs fast and smooth for about 5 minutes then suddenly looses power and runs like it is about to jump off the boat. Anyone run across anything like this? Maybe electric? gas? any suggestions greatly appreciated

 

[Scott Danforth]

check your fuel system. grab the factory manual and start troubleshooting

 

[flashback]

Does it continue running rough or does it eventually quit running?

 

[racerone]

Water pump impeller changed every 5 years ?

 

[99yam40]

over heating or low on oil (if it is an oil injected motor) will put the motor into RPM reduction mode to let you know the motor has a problem just in case your buzzer/horn and gauges are not working properly

 

[sambrigman]

after it cools it will run again

 

[racerone]

Did you replace the impeller ?

 

[sambrigman]

motor stays cool to touch, new water pump

 

[airshot]

Does the squeeze ball in the fuel line remain hard or does it go soft ? Try squeezing the ball and see what happens when it acts up. How old is the fuel line ?
Need more info to make suggestions.....