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  1. #1

    1999 sltx cold start

    So my ski takes a while to get fuel when it’s cold.
    Is this how they all are ?

    once it starts once, it will re-start immediately.

    Seems all the fuel drains back in tank, and it takes a while to come up while cranking .

    I’m surprised there isn’t a one way check valve or something .
    Last edited by K447; 10-15-2021 at 08:31 PM.


  2. #2
    Click avatar for tech links/info K447's Avatar
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    If you prime the carb intakes with a dribble of fuel down each, does it start right away, cold?

    Is the factory choke system in place and working?
    Are you using it?

    What original parts are in the fuel system, between the liquid fuel inside the fuel tank and fuel pump, that may have aged and be leaking air into the fuel hoses?

    Fuel selector valve replaced?

    Fuel-water separator (if present) o-rings replaced?

    Old fuel hoses?

    Gear clamps used on the fuel hoses? These often crush the fuel hose or create a tiny air gap under the clamp where the gear is.

    Bear in one that the fuel pump works by creating a suction in the fuel hoses from the tank. And air leaks, even small ones, can frustrate the fuel pump’s efforts while the engine is cranking.

    Not only does the fuel pump take longer to draw fuel despite the air leaks, those same air leaks can allow the fuel to drain out of the fuel hoses when the engine is not running.

    Sometimes (not often), but sometimes, the fuel sender unit that sits in the tank can have an air leak at the top, where the metal fuel nipple tubes join the vertical aluminum extrusion inside the tank. An air leak at the top of the fuel sender can also allow air in and encourage fuel flow back into the tank from the fuel lines.

    As a test - disconnect the fuel feed hoses from the fuel pumps.
    Plug the hose ends.
    Disconnect the fuel tank vent hose and cap that at the tank.

    Disocnnect the fuel return hose at the tank. Connect that to a controllable vacuum source with vacuum gauge and valve.

    Create a mild suction inside the fuel tank and then seal it in with the valve. Monitor the vacuum gauge to see if the system can hold that mild vacuum for a few minutes without declining.

    Do not get aggressive with the suction, just apply enough to see if the fuel system is sealed. You do not want to collapse the fuel tank sides.

    If the entire fuel tank and feed hose system really is air tight, then look at the fuel pumps on the carbs. Perhaps there is a gasket, check valve flap or other problem that is allowing air into the pumped fuel areas.

    While you are in there, make sure the carbs really are 100% air sealed to the intake manifold and the manifolds are sealed to the engine at the reed cages.

  3. #3
    sdlvx's Avatar
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    In addition to everything K447 said, I had problems on one of my skis because I replaced a 2 PSI vent check valve with one with no pressure.

    When you start it, if there's no trapped air pressure in the tank then the fuel pumps have to work extra hard to get it started.

  4. #4
    Carbs just rebuilt . All new hoses , no fuel shut off . I bypassed it because I need a new one . The only hoses I didn’t replace , was the fuel pump hoses because they looked like they had been done .I could have a small leak in one of the hoses .

  5. #5
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Jimmyg69 View Post
    Carbs just rebuilt .

    All new hoses , no fuel shut off .

    … I could have a small leak in one of the hoses .
    Carb base gaskets - 100% good sealing to the manifold?

    My recommended hose clamps are Oetiker stepless/gapless ear clamps. Choose the correct clamp size for your hose OD and you will have perfect hose to fitting sealing at every hose end. They cannot loosen with vibration and they provide a controlled spring grip all around the hose.

    Especially for the small diameter fuel hoses, for which I find both zip ties and gear clamps to be sub-optimal.

    Carb rebuild kits, genuine OEM or aftermarket?

    Fuel pumps also rebuilt?

  6. #6
    I used the hose viper pilot recommended, tygon . I bought the appropriate spring clamps . Rebuilt the pumps .aftermarket rebuild kit , but american made . I’m gonna replace the fuel pump hoses next . Could fuel sender be clogged ? havent taken tank out yet . Just finished drive coupler bearing .

  7. #7
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Jimmyg69 View Post
    I used the hose viper pilot recommended, tygon .

    … replace the fuel pump hoses next …
    How stiff is that Tygon fuel hose?

    The proper marine grade fuel hose is double wall fuel hose with fiber mesh reinforcement in between the layers, with the USCG marine grade rating printed on the outside. Makes for fairly firm hose that cannot easily kink or collapse under suction.



    The pulse hose that connects the fuel pump to the crankcase side port depends upon the hose being stiff enough to not expand and contract as the rapid pressure and vacuum pulses transit the pulse hose to power the fuel pump.

    It would seem there is a range of products sold with the Tygon name. Some are intended to be used for fuel hoses, some are not. None are rated for use in a marine environment, let alone inside an enclosed non-power vented PWC hull.

    Reading some of the info from SGPP it would seem that the desirable product would be Tygon® LP1200 fuel hose.
    Tygon LP1100 may be too flexible for use as a pulse hose. For fuel supply hose, does it have enough wall stiffness?

    https://www.hemmings.com/stories/201...t-use#comments

    Yves Legrand 6 years ago
    Calling Tygon a clear a gas-resistant vinyl tubing makes really no sense.

    Tygon is a generic name for all the Saint Gobain flexible hoses. SGPP (Saint Gobain Performance Plastics) has 4 grades of "Tygon" fuel resistant tubing (LP1100,LP1500, LP1600, F-4040A) each for a specific application and several dozen that are just not compatible with any fuel...

    I am currently investigating the fuel line subject for ultralights and a common local (french namely) "fashion" is to use purple hose....unfortunately I was not yet able to get the "purple" spec except it's supposed to be PU ...spooky for me !

    Best regards

    Yves

    in reply to Yves Legrand
    Dave S
    I once made the mistake of buying a "stock" length of genuine yellow Tygon from a "pro" ebay seller. Within a month of sitting unused in the box it had come in, I noticed the coil was staining the paper packaging. I pulled it out and got sticky residue on my hands immediately. Seller stonewalled and ebay averted its eyes. I checked with St Gobain to see whether this was common or a "bad batch" and they indicated that there was a surprisingly-short shelf-life for the stuff, like...a year? Seriously?

    In denial of the ripoff, I kept the box around until it had literally soaked through with the nasty out-goo. St. Gobain had little to say in response to my question about what this stuff would do to a fuel system, since it's certainly not /only/ coming out of the outside of their hose.

    I'd bought short lengths of Tygon fuel-rated hose in years past and did eventually find that in use, it stiffened to the point of being unusable but never had this "goo-ing" experience. No more for me.
    https://www.processsystems.saint-gob...rent-or-opaque

  8. #8
    I suggested LP1100 since that's what all of the guys in our area, Polaris machines or not, are using for anything that touches fuel. Not sure if it's the most perfect option in the world, but with all of the problems I've had with this Polaris crap, thankfully the fuel lines haven't been an issue for me. If I made a bad call, I'll take the hit. Not sure jimmy would be having problems with brand new line though. I could understand old stuff used for pulse lines that might be collapsing, but I haven't seen any signs of pulse line collapse on my machines that have new line. That was one of the things I was staring at hard when diagnosing my no-start problems. Again, a sample of 1, so take it with a grain of salt.

  9. #9
    Click avatar for tech links/info K447's Avatar
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    Quote Originally Posted by Viper Pilot View Post
    I suggested LP1100 since that's what all of the guys in our area, Polaris machines or not, are using for anything that touches fuel. Not sure if it's the most perfect option in the world … the fuel lines haven't been an issue for me.
    If I made a bad call, I'll take the hit.

    … I haven't seen any signs of pulse line collapse on my machines that have new line. …
    I have never used Tygon for fuel or pulse hose on any of my 2-stroke engines.

    I have not handled nor compared the various ‘grades’ of Tygon hose, so I do not have direct experience to which Tygon version might be optimal. I do know I have encountered ‘generic’ clear/colored fuel hose installed on other people’s engines that was simply too soft to work well as fuel hose and especially for the pulse hose.

    I am also here to learn. If the Tygon LP1100 product is ‘just fine’ for this purpose, good to know. If LP1200 is better, someone with that info would have to comment. If neither is appropriate I cannot say, beyond noting that apparently none of the Tygon products are USGC rated marine grade.

  10. #10
    I used tygon 40-40 premium pvc fuel and lubricant hose . It’s ethanol safe
    Last edited by Jimmyg69; 10-16-2021 at 06:06 PM.

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