Troubleshooting with Steve Rothwell

GENERAL

SU CARBURETTOR

Q Your series on various makes and models are brilliant – keep up the good work. Can we have an article on the SU HIF 44 carb? I have one on an MG Midget 1275 engine in a special that I have built which keeps on flooding. Although having played around with the old SU carbs a great deal on Imps and Minis, I do not understand the HIF carb and cannot stop the flooding. I am sure many would be pleased to see an article on them.

David Price

The HIF (horizontal integral float chamber) SU carburettor was designed with a view to reducing emissions, and it operates in much the same way as the earlier unit, although the jet operation and adjustment is slightly different. Instead of being beside the carb, the float chamber was incorporated into the main body with the float shaped around the main jet. The fuel route into the carburettor is still controlled by a needle valve operated by the float, which is lightly spring loaded. Flooding of this carburettor is