SU Carburetor Tip


Thought I’d pass on a tip to keep SU carb’s functioning during storage. I have a couple of mini’s with twin SU’s but this also applies to a single as well, in this case HS 2 or HS 4’s, perhaps others as well. HS style SU’s have an external float bowl vent tube that vents to open atmosphere. The problem is that over time if you don’t start and run the car on a regular basis (of course you do?) the fuel in the float bowl will evaporate, even down the the jet and needle which turns fuel/petrol into a resinous gum making it impossible to even raise the piston in extreme cases, resulting in the need to rebuild the carb(s) to sort the issue. To prevent this, go to your local auto parts store and buy an assortment of plastic vacuum caps and place over the end of the float bowl vent tube which prevents evaporation. Just remember to remove them when starring the motor again. If you forget, the car will tell you as it won’t start or run long if it does, with them in place.

See yellow vacuum cap. A way cheaper alternative to buying rebuild kits and the time spent to rebuild and re-tune or worse if you pay others to do the same…