2002 Yamaha 50HP 4 stroke idles smoothly but misses when run full throttle

[BMG1950]

Any ideas where to look for the problem? Mechanic checked carburetors and changed spark plugs but still not fixed. Charged us $600 and still not fixed. Motor idles fine but misses when we try to run it on open water.

 

[pas_bon]

I find another mechanic! Next I'd suspect the carb. When you run it wide open it up it may be starved for fuel. Also take it back a demand better service for your $600!

 

[jasoncalleja]

I will check the fuel pump and fuel line and tank as for me it is starved for fuel

 

[papyson]

pump the bulb and see if it makes a difference....depending on its location you may need a 2nd person in the boat...if he is at the rear of the boat and behind you be careful as the speed may be varying...surging....

 

[racerone]

Use a timing light to determine if it is a spark issue.-------Test each cylinder.

 

[Tommy's]

I had the same on my yamaha 50hp IT WAS STARVED OF FUEL WOULD EVEN STALL If I echelons rated to quick

try a carby cleaner like sea foam and run that through also replace the fuel filter and check fuel tank for contaminants