150hp 0x66 cuts out

[3gulls&abuoy]

Help! The last two seasons my saltwater series 2 has had a problem that is getting worse. Cruising along it acts like you pulled the throttle back then flares right back to speed just to pull back again. Found it wouldnt fail if i stay below 3k rpm. Also temp fixes if you turn motor off for a minute. Have ran many tanks of fuel, replaced impeller(it was overdue) tstats check good. It will act up after crossing a wake or making a turn. I bought this new (99) and havent replaced anything but impeller. Fuel pump? 02 sensor?<br />Thank you!!!

 

[rodbolt]

Re: 150hp 0x66 cuts out

well its so far past any maint schedule its not funny<br /> test the compression first.<br /> if no mechanical damage has occured from neglect then proceed to the maint schedule.<br /> you will need to clean and test the 02 sensor., use the test harness not the flame test. the most likly cause is the filter on the high pressure pump in the VST. but there is a tremendous amount of maint to do. your problem sounds fuel related and its common. after catching up on the maint and if the problem is still there test fuel system vacum. while your at the dealer buying parts ask for a copy of the two pages from the 05 marine tech guide on the maint schedule for the OX66 EFI. take note the schedule is by hours OR calander whicever occur first. you will need a high pressure fuel gaauge and the O2 sensor test harness.an O2 sensor failure can lead to a piston failure due to the computer will react to bogus info a clogged sensor sends it. if it leans out to much, POOF, no piston. usually on #1.

 

[3gulls&abuoy]

Re: 150hp 0x66 cuts out

thanks, i have neglected maint other than lower unit oil and plugs, but it has been an incredible engine. I think it may have started after i noticed some water in fuel bowl. Thanks for all your help!!