High Pressure Pump OX66

[Anthony 92]

hey guys. so i checked my HP today and i was getting 32 PSI and it all of a sudden drops drastically to like 25 or so. the clymer guide have indicates 41-51 PSI for EFI models and 35.6 for HDPI models.

should a 200HP ox66 saltwater series 2, have a fuel pressure of 35.6? or is the clymer guide correct for the EFI model?

i am thinking bad or weak pump or fuel pressure regulator?

i have replaced the CDI, Pulsor coil, stator new plugs.

the issue is still when given throttle on load, it dies. if you advance the throttle while not in gear it revs fine.

 

[boscoe99]

The fuel pressure will vary. As a function of engine manifold pressure.

Highest pressure at key on, engine off.

A different pressure when the motor is running but at an idle.

As the throttle is opened up the fuel pressure should go up. Throttle retarded the fuel pressure should come down.

 

[boscoe99]

Having no idea which OX66 model you have, I cannot check to see what a Yamaha service manual says the pressure should be.