Solex carburettor

[Bob CrossParticipant]

 

Hi,

I have a 1949 Slough-built Big Six. A ‘  flat spot ‘ developed on accelerating  – a momentary hesitation when the accelerator pedal is depressed. The car was fitted with a twin-coke Solex carburettor 30PAAI with a depression-type carb. pump rather than the more normal mechanical lever-operated pump. I changed this to a mechanical pump (I have a spare carb with a mechanical pump though only fit for spare parts) I’ve cleaned all the jets, new pump diaphram, new gaskets. Checking the carb on the bench, still only  a trickle came from the twin curved pipes into the chokes of the carburettor and there was a return of fuel/air into the float chamber! However, I have discovered, that what I assume is a pressure relief valve, was rising slightly,(see photo) . If this is held down two excellent jets of fuel are discharged into the twin chokes and there is no return of fuel/air into the float chamber! I cannot see how this pressure relief valve (if that is what it is) can be adjusted or indeed removed altogether – no slot for a screwdriver or hexagon for a spanner.                     Any ideas/advice would be welcome

Bob Cross

 

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