Logo

2001 OX66 150HP High Fuel Pressure reading

Thor Outlaw

New member
Hey All,

Ive got a 01 150 OX66 with a new power head (approx 70 hours). Ive had trouble with idling high, sometimes low and surging at higher RPM. I bough the motor from a marina here on Long Island with a 1 year warranty (now expired). Ive taken the boat back to the marina multiple times for my idle issues. I've been assured that it was fixed by a link and sync adjustment only to run into the same problems not long after.

Recently, I sent my injectors out for cleaning and received them back (all passed and were serviced)- I ran the motor and experienced same surging and idling issue. Last evening, I put a fuel pressure gauge on the schrader valve (on VST) to find that my fuel pressure at idle is 42PSI, taking my RPMS up to 1400 raises my fuel pressure to 54PSI! My manual says 36-37psi through the RPM range.

Ive eliminated clogged filters as the HP pump strainer is clean, the fuel regulator basket strainer is clean and the injectors have just been serviced. Both LP pumps are new as is the O2 sensor, I made sure the sniffer tube was clear as well.

Anyone have any other ideas? This evening I'm going to check for vacuum on the hose going to the fuel pressure regulator, if vacuum is found is it safe to assume that the regulator has failed?? Is there a clear way to test the regulator? Google searches would indicate this is not a common part failure.

Thanks for any help-
 
A vacuum pump can be used to test the regulator. As the pressure is lowered and raised on the regulator the fuel pressure should follow.
 
A vacuum pump can be used to test the regulator. As the pressure is lowered and raised on the regulator the fuel pressure should follow.
Thanks for the assistance. I put my vac pump on the regulator and at idle with some vac on the diaphragm i was able to bring the pressure down from 40psi to 37ish. However, raising my rpms to 1400 sends the fuel pressure to 54-55psi. I believe the regulator is faulty.
 
Back
Top