I have had the SU from the Lambda with Ian Ruffley for the last week as it was running so rich that even hot spark plugs (NGK B4ES) were carbon fouling. Ian found the following.
- I have a reasonably recent SU it should not have a vent in the dashpot cap as it already has an internal vent so the dashpot circuit had a permanent leak.
- The main jet was oval as it had not been centred.
- The thottle butterfly had been replaced at some time but it didn’t fit the hole.
Ian rectified all the above. Next I fitted the inlet manifold and took a photo as I couldn’t get my boofhead around the back of the engine and found a bit of a step between the head and the manifold. The Lambda has a reproduction aluminium head and it appears that things like studs and ports are not quite where they should be. It was suggested by Andrew C. that a half round file may do the job so I duly stuffed a rag into the inlet port and filed away, after a few trial fits all was good.
Carburettor was refitted and after Glenn pointed it out to me, spark plugs were also fitted (NGK B6ES). Choke on, hit the starter and immediately settled to a good idle.
At some point while we were cleaning up Glenn asked me if I had taken the rag out of the inlet port, he didn’t ask me this because he has a great memory it was just that about 2 metres behind the car were a couple of fragments that looked familiar…..