95 Waveraider 1100 not getting vac pulse to fuel pump
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  1. #1
    PWCToday Newbie
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    95 Waveraider 1100 not getting vac pulse to fuel pump

    Hello, need some ideas on a 95 Waveraider 1100. Recently removed carbs and rebuilt them to try and solve a missing midrange. Ski ran fine @ idle and full or close to full throttle. After reinstalling the ski is not getting fuel. Checked the fuel pump manually and it works fine. Sucking on the fuel supply line I can see the filter filling with fuel. Stuck a combo vac/psi gauge on the crank port and I have very little fluctuation on the gauge. Compression measures 95, 100, 100. Ski ran fine last year and will run on a shot of ether/fogger. What would cause the ski to all of a sudden loose signal at that port? I've looked but don't see any other vacuum ports. Thanks in advance

  2. #2
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 95 Waveraider 1100 not getting vac pulse to fuel pump

    Quote Originally Posted by Blackbird View Post
    Compression measures 95, 100, 100.
    Ski ran fine last year and will run on a shot of ether/fogger.
    Both statements are concerning. Obviously your compression gauge reads at least
    25 psi low. But the 5 psi difference is significant on watercraft. It could be a sign
    that rust damage exists in the low cylinder, or some kind of top end problem.

    Just as an example a piston seizure will often test the same as a piston that didn't
    seize.

    Second, the ether. You are describing a problem where the needle and seat isn't
    opening. This problem is often misdiagnosed as a fuel pump problem. It is often
    caused by a loss of manifold vacuum (a vacuum leak or engine problem).

    Quote Originally Posted by Blackbird View Post
    After reinstalling the ski is not getting fuel.
    Checked the fuel pump manually and it works fine.
    Did you replace all of the intake manifold gaskets?

    Did you check out the reeds?

    Quote Originally Posted by Blackbird View Post
    Stuck a combo vac/psi gauge on the crank port and I have very little fluctuation on the gauge.
    You will get better results if you use a 1-way check valve to test pressure and
    vacuum separately.

    Quote Originally Posted by Blackbird View Post
    What would cause the ski to all of a sudden loose signal at that port?
    Obviously what ever the problem is, it has been going on for quite a while.




    Bill M.
    Last edited by wmazz; 05-18-2019 at 08:03 PM.
    Horsepower == Speed, RPM != Speed



  3. #3
    PWCToday.com Is My Home Away From Home Grumpy Old Guy's Avatar
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    Re: 95 Waveraider 1100 not getting vac pulse to fuel pump

    My guess is you have the fuel pump hooked up wrong...easy to do on the 1100.

  4. #4
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    Re: 95 Waveraider 1100 not getting vac pulse to fuel pump

    Bill, thanks for the reply.

    Ski is definitely old and tired but she idled and ran well at full or almost full throttle last season.

    My first problem is the ski is not getting fuel, non, zero, zippo, so if the needle seat is open or closed isn't going to matter, yet. The ski is not getting fuel because the fuel pump (stand alone pump on RA1100, not per carb) is not getting a pulse from the crankcase. With the pump off the ski I can alternately suck/blow (no jokes please) on the pump port and it pumps fuel like no tomorrow. Typical diagnosis would point to something I did with the carbs seeings how it was running before I messed with them but, with the pulse port being on the crank side of the reed valves I'm thinking that may eliminate them from the equation...

    Quote Originally Posted by wmazz View Post
    Both statements are concerning. Obviously your compression gauge reads at least
    25 psi low. But the 5 psi difference is significant on watercraft. It could be a sign
    that rust damage exists in the low cylinder, or some kind of top end problem.

    Just as an example a piston seizure will often test the same as a piston that didn't
    seize.

    Second, the ether. You are describing a problem where the needle and seat isn't
    opening. This problem is often misdiagnosed as a fuel pump problem. It is often
    caused by a loss of manifold vacuum (a vacuum leak or engine problem).



    Did you replace all of the intake manifold gaskets?

    Did you check out the reeds?



    You will get better results if you use a 1-way check valve to test pressure and
    vacuum separately.



    Obviously what ever the problem is, it has been going on for quite a while.




    Bill M.

  5. #5
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 95 Waveraider 1100 not getting vac pulse to fuel pump

    Quote Originally Posted by Blackbird View Post
    Ski is definitely old and tired but she idled and ran well at full or almost full throttle last season.

    My first problem is the ski is not getting fuel, non, zero, zippo,
    I would prefer that you test the fuel pump output while it is connected to
    the engine.

    Quote Originally Posted by wmazz View Post
    You will get better results if you use a 1-way check valve to test pressure and
    vacuum separately.
    Most manufactures use a 1 way valve on the fuel tank vent line. You should
    see ~7 psi & ~ in-hg on your gauge. You can usually find 1 at a NAPA auto parts.

    Next I would like to know how well it pumps fuel into a container or static fuel
    pressure @ your psi-vac gauge.



    Bill M.


    A lot of people on PWCtoday rode their triples on 2 cylinder, and still didn't
    realize they had a serious engine problem. I am very curious about the poor
    midrange power, and which cylinder was low on compression.

    Attached is a similar vac/pressure gauge I used to evaluate Kawasaki main
    seals with.
    Attached Images Attached Images
    Last edited by wmazz; 05-20-2019 at 11:13 AM.
    Horsepower == Speed, RPM != Speed



  6. #6
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: 95 Waveraider 1100 not getting vac pulse to fuel pump

    Quote Originally Posted by wmazz View Post
    you should see ~7 psi & ~7 in-hg on your gauge.
    7 & 7



    Bill M.
    Last edited by wmazz; 05-21-2019 at 04:41 AM.
    Horsepower == Speed, RPM != Speed



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