Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 9 of 9
  1. #1

    Default 1999 Yamaha Vmax 150 0x66 fuel problems?

    Running a tournament last week, my 1999 Vmax 150 trp 0X66 fuel injected motor bogged down and stalled anytime i went over 3/4 throttle.

    I checked the usual and there is no water in the tank or in the system.

    Has anyone had this problem before?

    It runs normal to 3/4 throttle put anytime i go over that it boggs and stalls out. Any ideas?

  2. #2
    Petty Officer 1st Class
    Join Date
    Apr 2009
    Location
    Supply NC
    Posts
    241

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    I just corrected such a problem with a 2000 model 150 throttle body injected.

    I removed the "fuel delivery assembly", opened it up and removed what was inside it.

    It appears to be a check valve with a fancy name, or a back flow preventer. After unscrewing it and taking out the piston and spring, I put it back in line and the motor runs fine after the water test.

    You'll find it in line, between your engine fuel filter and the fuel pumps.

  3. #3

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    you dont hav a picture of the piece do you?

  4. #4
    Petty Officer 1st Class
    Join Date
    Apr 2009
    Location
    Supply NC
    Posts
    241

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?


  5. #5

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    Did you replace it? Or just take it apart and put back in?

  6. #6
    Petty Officer 1st Class
    Join Date
    Apr 2009
    Location
    Supply NC
    Posts
    241

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    As stated above, I took out what was in it and put the assembly back in without the piston and spring.

    It could also be an issue with your anti-siphon valve at your fuel tank pick up.

    Read my post below yours.

  7. #7

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    what was in it? Junk?

  8. #8
    Petty Officer 1st Class
    Join Date
    Apr 2009
    Location
    Supply NC
    Posts
    241

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    Nothing in it that I could find as far as trash. I figured it wasn't operating properly for whatever reason.

    I couldn't blow through it against the arrow/flow, and when I blew in it in the direction of flow, it would stop up quickly then open a bit then stop up again, just like the engine was doing when stalling.

    Maybe someone on here can give specifics as to what a fuel supply assembly is supposed to do.

  9. #9

    Default Re: 1999 Yamaha Vmax 150 0x66 fuel problems?

    Yamaha is 1 week away from getting me the item 24, I have since replaced the plugs and the fuel filter. Any other help would be great!!!

Similar Threads

  1. Going broke with 0X66 fuel system problems
    By tbn43 in forum Yamaha & Suzuki Outboards
    Replies: 2
    Last Post: July 12th, 2008, 08:05 PM
  2. 1999 Yamaha 0X66 powerhead blown help
    By keithscatch in forum Yamaha & Suzuki Outboards
    Replies: 3
    Last Post: June 28th, 2007, 12:45 AM
  3. Yamaha 250 0X66 SS fuel problems?
    By stupidfly in forum Yamaha & Suzuki Outboards
    Replies: 4
    Last Post: March 31st, 2004, 12:55 PM
  4. 1999 Yamaha Vmax- good or bad???
    By 2000Fisherman in forum Yamaha & Suzuki Outboards
    Replies: 1
    Last Post: June 6th, 2003, 06:32 PM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic