Page 1 of 3 123 LastLast
Results 1 to 10 of 23
  1. #1
    Join Date
    May 2018
    Posts
    10

    Default Fuel issue indmar 325

    99 santera 325 indmar. Just bought boat so I don’t know the history. When it’s towing around 10 to 15mph will run perfect for a few minutes and all of a sudden just looses power and starts shuddering and backfires but will idle. Turn off for a minute or two and works fine for a little bit and does it again . Runs great at idle or just above, and will run perfect all day long going 20 mph plus. When it happens if feels like the fuel pump is shutting off and your running on fumes. I have searched all over but mostly what I find is boats that will not run good over certain rpm.
    99 santera

  2. #2
    Join Date
    Dec 2013
    Posts
    645

    Default

    Is it a carb or FI? Is the pump mechanical on the block or electric?

    In general, your description is exactly how a failing fuel pump acts. The twist is usually a weak pump will not run well at high speed...meaning temperature may be an issue, but still fuel related. If you have a carb I would think vapor lock while running hard at lower speeds. If it is fuel injected, then 100% fuel pump related.

    Of course this assumes you have changed your fuel filter, which is always the first step with engine problems.

  3. #3
    Join Date
    Jun 2012
    Location
    Knoxville TN
    Posts
    1,415

    Default

    ^^^ +1 on the fuel filter.

    Not that it's related to your fuel issue, for a new boat to you, I would also check the simple tune up items at that start of the boating season - plugs, cap, wires. Easy replacements that could eliminate some headaches later. You may already be on top of that.
    2018 Supra SL400

  4. #4
    Join Date
    May 2018
    Posts
    10

    Default

    Fuel injection. I have put on new fuel line, and new filters. There are two fuel pumps (carter low pressure & the factory high pressure) also both fuel pumps are connected to the same wires.
    99 santera

  5. #5
    Join Date
    Jan 2011
    Location
    Charlotte, NC
    Posts
    44

    Default

    You sure it's not boat temp related? Mine will do stuff like that when the computer goes to shutdown mode if it's overheating. Usually this is because some crap is clogging up the transmission cooler. Boat can't flow enough cooling water and overheats. But at higher speeds the load is lower and the pump works harder, so the engine cools back down.

  6. #6
    Join Date
    May 2018
    Posts
    10

    Default

    I’ll check all the cooling lines screen and pick up out but I’ve never seen it get over 160. I have to do some work on my gauges to cause half of them don’t work most of the time.
    99 santera

  7. #7
    Join Date
    Dec 2013
    Posts
    645

    Default

    It sounds most likely the connection to the HP pump, or the pump itself is failing intermittently. If the low pressure pump is an add on, it could be pulling enough amperage to affect the HP pump.

  8. #8
    Join Date
    Dec 2012
    Location
    Clark, CO.
    Posts
    587

    Default

    I would check your throttle position sensor. Also install a fuel pressure gauge up by the intake and see what it reads when this happens. I'll bet the pump is fine but this is the only way to know for sure.
    Function before fashion!

  9. #9

    Default

    Hook up a fuel pressure gauge to the schrader on the rail, and watch the pressure while you drive. Should be around 48 psi pretty much all the time.

    The problem with the gauges is almost definitely the MDC. Check my recent thread.

    https://forum.supraboats.com/showthr...h-Dash-Rebuild

  10. #10
    Join Date
    Dec 2012
    Location
    Clark, CO.
    Posts
    587

    Default

    Throw away the mdc. Here is my thread, Same boat.
    https://forum.supraboats.com/showthr...head-questions
    Function before fashion!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •