SBT Jetski Engines, Parts & Accessories

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  1. #1
    ADub is offline Showing off on the beach
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    Default Won't start after carb rebuild

    Previous owner said it ran, but it needed a carb rebuild. 98 770R. I rebiult both carbs and now it won't start. Its got spark, but its not getting fuel. I cannot find any external leaks. Pulse line is clear, pulse port holds pressure, fuel filter and lines are clear. What else can I check? I'm pretty sure I put the pump back together correctly, but I have no idea why I'm not getting fuel now.

  2. #2
    ADub is offline Showing off on the beach
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    Default Re: Won't start after carb rebuild

    I am getting fuel coming out the accelerator pump, but no fuel is coming into the filter to replace the fuel that went out

  3. #3
    ADub is offline Showing off on the beach
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    Default Re: Won't start after carb rebuild

    So I have decided that the problem is that I can't pull fuel from the tank. How do I pressurize the tank or bleed the lines to get fuel up to my filter?

    I pulled the main and reserve lines, plugged them and tested the switch, it holds pressure just fine.
    Last edited by ADub; 09-05-2005 at 08:17 PM.

  4. #4
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    Default Re: Won't start after carb rebuild

    If you blow into the return line you should get fuel out the supply line. The supply line goes to the bottom fitting on the carb and the return line goes to the top fitting. The center pulse fitting connects down onto the crankcase fitting.

    Now when you try to start it you should be getting fuel flow out of the return fitting on the carb. Unplug it for a test and check. If no fuel is flowing out and all lines are connected up with clamps and the crancase is providing pulse to the fuel pump then the fuel pump is still not working.
    Providing mobile JetSki service to the Charlotte / Lake Wylie area.

  5. #5
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    Default Re: Won't start after carb rebuild

    Pressure testing isn't always the answer. Remember, to draw the fuel from the tank, the pump creates a vacuum in the line and the atmosphere pushes on the top of the fuel in the tank, forcing into the line and into the pump. If there is a leak into the fuel system, the vacuum may formed may be insufficient. The fuel selector valve is the high point in the system. A leak here will really kill things.

    Also, reed valves in the pump MUST sit flat and tight to the base plate. Push on them quicklygently, if you hear them seating (a small tap), they are bent, and no good.

  6. #6
    ADub is offline Showing off on the beach
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    Default Re: Won't start after carb rebuild

    In hindsight, I'm not sure I fully tested the selector. I will check it again tonight more thoroughly. I don't think the pump is my issue. If I remove the supply line from the carb and put vacuum on the supply line, I still don't get fuel.

    So say the switch is leaking, can I just run a line straight from the reserve pickup to the fuel filter to get it running and worry about fixing the switch later?

  7. #7
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    Default Re: Won't start after carb rebuild

    Just as quick test, you can throw a vacuum gauge on the pump inlet, and see if the pump pulls a vacuum, just to satisfy yourself.

    Rather than using the reserve line directly, would it be easier to runn the engine from a very small container? If you do the reserve line thing, I wouldn't leave it that way longer than it would take to test. You might gravity feed fuel through the carb into the engine undesireably.

    Keep in mind that air has to get into the fuel tank to push the fuel out. If the inlet air check is installed the wrong way, you'll eventually have a vacuum in the tank air space, and fuel won't flow.

  8. #8
    ADub is offline Showing off on the beach
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    Default Re: Won't start after carb rebuild

    If the switch is bad, then I plan on bypassing it so I can use the ski a few times before winter, then worry about the switch in the off season. If I routed the new hose similar to the current routing so that the highest point on the hose is the highest point in the system, I don't see how it could be any worse off that it is with the switch. I am new to the mechanic side of jet skis though.

  9. #9
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    Default Re: Won't start after carb rebuild

    Good plan, but you may still be hampered by siphon action once the hose is void of air. Siphon action will occur when the source point Gas tank) is higher than the delivery point (the carb), and the hose between is filled with liquid.

  10. #10
    ADub is offline Showing off on the beach
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    Default Re: Won't start after carb rebuild

    Gotcha, makes sense

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