998 Fuel Pump Assembly (submersible Fuel Lines)

Discussion in '748 / 916 / 996 / 998' started by Nick_996, Jun 21, 2026.

  1. Been hearing some squirting noises from the fuel tank on start-up and I am led to believe that a submersible fuel line from the fuel pump assembly has very likely failed/split. With the fuel cap open and once the fuel pump primes, I can see some small squirting activity too but can’t actually see where/what the issue is (https://canva.link/xhk3u9f801hckg1). The bike still rides fine regardless, as was shown by a rather cheeky thirty-minute drive earlier today.

    By way of pre-emptive maintenance and since I’ll be taking the fuel pump assembly out for the very first time after the factory put it in, I’m contemplating to replace pretty-much everything on it (other than the fuel pressure regulator and the base fuel assembly flange/plate where everything bolts on).

    Most submersible fuel lines are no longer available to order from the factory and was wondering whether any of you have found a reliable source for alternatives of equal (or better) quality to do the job. From the factory discontinued fuel lines, some appear curbed but can’t see this being an issue if a non-curbed alternative is found/sourced instead.

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    #1 Nick_996, Jun 21, 2026
    Last edited: Jun 21, 2026
  2. if the bike is performing well and you can't sense any issues when using the engine through all ranges, then it's probably fine isn't it? It's perfectly normal to see and hear fuel returning to the tank as it's purely excess fuel that's not needed, at mainly engine idle speeds.

    it is true that with time, the hose that's used in your fuel tank will break down, resulting in a loss of pressure, but this would be accompanied by erratic engine running behaviour at early stages, going onto engine very reluctant to start and impossible to put a load on it, at the worst case.
     
    #2 Chris, Jun 21, 2026
    Last edited: Jun 21, 2026
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  3. Listen to the Tank: Open the filler cap, look at the fuel while bike is stationary, wait for it to level out. Turn the key on. Does the fuel pump prime with a crisp, solid 2-second whirrr, or does it sound like a hollow, bubbly gurgling inside the tank? If it gurgles, your internal tank lines are gone.
     
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  4. @NineNineSix this is what I think I've said above but now I've also posted a short video with sound here https://canva.link/xhk3u9f801hckg1
    I am pretty certain of the diagnosis though; my post is seeking input on the solutions side of things
     
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