Walbro carb onClinton 498

[charlie]

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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[charlie]

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

[will-haggle]

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…

[stuart]

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.

[wristpin]

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.

[hitchinsm]

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

[charlie]

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.

[andyfrost]

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.

[vhgmcbuddy]

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

Super bits of kit

[stuart]

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

[charlie]

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

[charlie]

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?

[charlie]

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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[vhgmcbuddy]

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!!

[charlie]

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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