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  1. #1
    olds72's Avatar
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    Help me understand Leak test procedure

    I put together my first ever engine. A 99/787 out of GTX RFI. It's been together for a few months now and since it's getting warmer here in OH, I want to put it back in my ski. I know it must be leak tested. I searched and read the threads, but I'm still a little confused. I've been reading the leak test section of the manual. It refers to testing the engine cooling system, bottom end, top end and rotary valve shaft. All of the threads I've read talk about testing the bottom end. Is this the only area I need to be concerned about? I have not read any threads referring to the RFI. Do I install the fuel rail for testing?.I'm making my own cover plates out of 1/2 inch plexi-glass. It came from a local ice arena. Will this work? I've made a cover for the exhaust manifold and one for the rotary valve opening. Do I need to remove the rave valves and make covers for those also? I bought a pressure gauge and accessories at the local hardware store. Where should I pressurize the engine from? Or where should I locate my schrader valve to pressurize? Thanks for the help.


  2. #2
    olds72's Avatar
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    38 views and no one understands or can explain the leak test to me?

  3. #3
    idoodou's Avatar
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    call 954-929-1636 ask for rob tell him idoodou sent you

  4. #4
    Hydrotoys's Avatar
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    Let me give you a giant overview, and see if it helps you to find out all the ports that need to be blocked off.

    -Imagine the air entering your carbs.
    -Anywhere that air can go once it goes past those carbs needs to be leak-tight.
    -This includes up-to the exhaust manifold sealing surface.

    -Block it all off.
    -Pressurize it to 10psi.
    -Wait a few minutes, and restabilize the pressure.
    -Go have a beer.
    -Come back and check it. If it dropped off you have a leak.
    -If it did not, assembly your engine.
    -Use soapy water in a spray bottle to look for leaks.
    -Your test equipment can leak, so don't forget that.
    -Once you THINK it's air-tight, go have another beer... maybe two.
    -Come back and check it. Rinse, repeat.

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