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+--- Thread: Engine Knocking.... (/showthread.php?tid=8002)
RE: Engine Knocking.... - Ian Williams - 18-11-2022
Virtually every A7 I have come across appears to run rich on the std carb, aside from wear and settings I believe this has something to do with the specific gravity of modern fuels being different to the pre-war offerings available when the jets were originally sized
RE: Engine Knocking.... - Tiger - 20-11-2022
Dennis my Ruby has always run rich.
I have tried fitting a washer under the needle valve to little effect
I am wondering whether the jets could be bigger after 80 odd years ?
The gasket you mention would lift and richen the mixture.
PS Good luck with the engine rebuild !
RE: Engine Knocking.... - Denis Sweeney - 20-11-2022
Tiger, I purchased a Zenith refurb kit for the carb and it included a new needle valve plus 3 aluminium washers of varying thickness to fit between the cover and valve. One was the same thickness as that fitted on my carb and the others were thicker. Perhaps I should fit the thickest and give it a try.
I am also still very interested to know what affect basically blanking off the slow running jet makes to the performance of the carb??
Any ideas anyone??
RE: Engine Knocking.... - Tiger - 20-11-2022
When I closed off the slow running screw the engine stopped as expected.