Results 1 to 2 of 2
  1. #1
    Member
    Join Date
    Oct 2019
    Location
    Texas
    Posts
    32

    2003 TZX190 w/ 150 VMAX Carb - Low RPMs?

    I've got a 2003 TZX190 with a 150 VMAX carb that I'm struggling to get more speed out of and I think it's due to low RPMs. The motor runs great and I've gone through the carbs by cleaning them out. I've also replaced bad needles, gaskets, etc. The motor runs great, no lean sneezes or dying at idle. Compression is good and consistent across all cylinders. I think the issue is either the prop, hotfoot, or height of the jack plate.

    I'm currently only able to get up to about 4800RPMs with the hotfoot that came with the boat. I trim up to the point my water pressure gauge reads between 15-20 PSI. For some reason I cannot get more RPMs out of the boat.

    I'm thinking either the issue is my hotfoot depressed all the way forward isn't actually moving the throttle cable to it's fullest position, prop isn't right, or jack plate isn't in the correct position. The prop is a 23M that I believe came standard with this motor.

    Anyone have any advice on where to start? Measure prop to pad and check throttle cable if it's being fully extended when the hot foot is depressed?

  2. Member
    Join Date
    Mar 2015
    Location
    Bixby, OK
    Posts
    2,280
    #2
    Definitely check to make sure you’re getting WOT when the hot foot is fully depressed. Set PTP at 3” and go from there. You should be able to go closer to 2.25-2.5. Last, but not least, trim it all the way up to obtain full speed. Skeeter’s like as much bow lift as they can get. If the prop is even in decent shape, you should be getting at least mid to upper 50’s if not 60.