Walbro carb onClinton 498

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  • April 10, 2016 at 5:15 pm #20461
    charlie
    Keymaster

    Thanks to parts supplied by Jon Cruse I have now rebuilt the magneto on my Clinton 498 and have a good spark. With a bit of fuel down the plug hole or poured in the carb it will fire and run briefly. That is where I now have a problem, the float chamber had filled with water at some time and was a bit of a mess. All cleaned out now and main jet is clear but I suspect idle jet fuel path is blocked.An article at How to properly rebuild a Walbro carb refers to removal of brass plugs. I cannot see how the method of prising them out with a small screwdriver is going to work. Has anyone any experience of doing this? Photos of my carb and the small brass plugs.

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    April 10, 2016 at 5:16 pm #20465
    charlie
    Keymaster

    Does anyone know if the number 9 76 stamped into the body below the number 200 is a date of manufacture?

    April 10, 2016 at 10:06 pm #20485
    will-haggle
    Participant

    I’ve now got 3 Clintons, I’ll have a look at the numbers tomorrow, mine are LMG The parts list for the 494 shows a plug kit as well as a rebuild kit…

    April 10, 2016 at 10:23 pm #20486
    stuart
    Participant

    The only way to remove the welch plugs is to drill a small hole through them and then prise them out with a thin screwdriver with the end ground down to a sharp point.Obviously the plugs have to be renewed so make sure replacements are still available before you do it.Clinton parts (new old stock) are still available in the USA on that auction site or you can make the plugs yourself.

    April 10, 2016 at 11:39 pm #20492
    wristpin
    Participant

    An alternative to the pointed object is a small self tapper gripped with mole/vice grips, just don’t screw it in too far and damage whatever is behind it. I’ve reused plugs after sealing the hole with Devcon or similar and a smear of Wellseal around the rim.

    April 11, 2016 at 5:25 am #20493
    hitchinsm
    Participant

    Where does it say it is a WALBRO, looks like an early Carter to me

    April 11, 2016 at 7:53 am #20494
    charlie
    Keymaster

    Stuart, wristpin, thanks for advice.
    hitchinsm, not shown is the float bowl which clearly says WALBRO made in USA and the model letters LMG agree with WALBRO model numbers.

    April 11, 2016 at 7:04 pm #20508
    andyfrost
    Participant

    Charlie , before you start trying to remove them , if you know anybody with an ultrasonic cleaner try that route first , they really are amazing bits of kit.

    Andy.

    April 16, 2016 at 10:20 pm #20537
    vhgmcbuddy
    Member

    I was just going to say the same about the sonic bath cleaner.

    Super bits of kit

    April 16, 2016 at 11:19 pm #20540
    stuart
    Participant

    I have one.If you want it doing Charlie send me a PM.

    April 17, 2016 at 8:32 am #20543
    charlie
    Keymaster

    A friend of my son has one, thanks for the offer.

    May 21, 2016 at 12:43 pm #20938
    charlie
    Keymaster

    Finally removed the brass plugs and cleaned out passage ways.
    Looking closely at the carb I cannot see how fuel gets from float bowl to any of the jets. I am wondering if there is a small hole that has become blocked when float bowl filled with water.
    Any one have any ideas?

    May 22, 2016 at 8:43 am #20940
    charlie
    Keymaster

    Photos of carb, the float bowl fits between fibre washers, so fuel cannot enter via threads on needle, there do not appear to be any other holes for fuel to get into carb.

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    May 22, 2016 at 6:40 pm #20945
    vhgmcbuddy
    Member

    Looking at the article you have provided a link to in post #1, in the 14th photo of the sequence it appears to show a small hole in one of the ribs on either side of the centre casting that the main jet is screwed into. My guess is that this hole is drilled into the rib, parallel with the main jet. There is then a cross drilled hole which runs through the rib and into the jet chamber. This cross drilled hole will have a plug in it. As you have the plug removed, see if you can insert a piece of wire and feel for the hole which should join into the cross drilled one behind the plug. I hope this makes sense Charlie. It’s very difficult to explain without being able to point!!

    May 23, 2016 at 8:47 am #20947
    charlie
    Keymaster

    busman, the hole behind the plug is clear, but I can see no way for fuel to enter this passageway. In desperation I have removed the filler I used to block the hole in the brass plug that I made to remove it. After a drop of fuel in the spark plug hole the engine fired and then continued to run. This supports my theory that there should be a hole to feed fuel through from float chamber.

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