[Roadsters] su chokes are backwards- they're 'enrichers' not 'stranglers'

[Toby B]

"That's back wards.

You pull the choke to start your engine. When you pull the choke, it restricts
the air flow into the carburetor thereby enriching the fuel mixture. You need
to enrich the mixture when the engine is cold."

Actually, on an SU, the main jet is lowered, adding more fuel to the mixture.
Additionally, the throttle plate's pulled open a bit to add air.  No
'strangler' for an SU, just a 'gasser'.

And thus, if your mixture is too lean, your jet set too low, your
float level's low or crud's built up on the inside of the jet body,
the car will only run 'on the choke' which is really 'on the enrichment lever'.

Weber DCOE's have an entire little carburettor to do what an SU does by dropping
the main jet a few mm.

Toby
Seattle.