[gazza2007au]

i just bought a boat with what looks to be a early 90's model yamaha 40hp i was told the motor has a problem with the oil injection fouling the plugs so instead of fixing the problem i would like to run the motor pre mixed how would i go about doing this? and does any know know where i can find a online diagram of the same motor's fuel pump this also needs rebuilding

[Ray Neudecker]

Sounds like they made a bad diagnosis. Problem more likely caused by a bad fuel pump or carbs that need going through. Replace the fuel pump and get a service manual for that model.

[JUSTINTIME]

yami's precision blend is the best out there
u can test the pump output, but they rarely fail

[gazza2007au]

i pulled the air filter off of the motor and the 3rd (bottom) carby was dripping with oil i than removed all 3 carbys and the 3rd continued to drip oil i now have all the oil injection blocked off and running pre mix still trying to get the motor to run but since the oil filled one carby i shouldnt have any problems
another question how hard is it to replace the water pump? im thinking i can just undo a few bolts and drop the lower end off is it that simple?