3A running very rich

[Geofftaylor]

My 3A has been running very rich for a while so I decided to carry out a full overhaul of the twin SU H6’s. There is no improvement and the car is still running very rich even with the jet screwed up tight and level with the face of the carb casing. Needles are set properly, float level set properly. Cant fathom this one! Any ideas?

[Lebro]

Do the pistons rise easily, are the right springs fitted, are the right jets / needles fitted.

Is the choke mechanism returning to the off position properly

Are the air filters blocked

Bob.

[Ralph Whitaker]

Sounds similar to the problem I had which originally was due to the overflow hole in the float chamber lids being blocked and the chambers pressurised.

Later I had a problem with the pattern part fuel pump having too much pressure and overcoming the Grosse float jets I had fitted. Initially cured by fitting a pressure regulator, but then later by going back to the original float jets and removing the pressure regulator.

Ralph

[billy l]

Hi Geoff, try to rig up a gravity fed fuel supply and run the engine just off that if it still runs rich the problem is with the carbs , if it runs ok then the problem is in the supply probably too much pressure. Cheers Bill

[mikej]

Perhaps also check the SM needles are properly seated (not too high). Remove a piston chamber and piston, hand pump the fuel pump and check that petrol level is below the bridge. Run without air filters until it's fixed.