Jaguar XKE Type Workshop
Rebuilding Dual Stromberg Carburetors
The carburetors in the Jaguar E-Type are mission critical. The performance of your car depends on them. As part of the fuel system, they can also raise safety issues as they can flood over with fuel and cause fire.
The original models of E-Types had triple SU carburetors. When emissions and safety standards went into effect, Jaguar went to dual Stromberg carburetors. My 1970 jaguar E-Type had dual Stromberg carburetors. There was nothing in my repair manual on these.
Rebuilding Dual Stromberg Carburetors (cont'd)
The key problem with my Jaguar was it would not idle correctly. Otherwise, the 4.2 liter engine ran well. The other problem on occasion with my Jaguar E-Type was fuel would sometimes pour out of the carburetors as if the fuel would not shut off. This is obviously a worrisome problem. After ruling out all the other possibilities, it came down to the carburetors. Both problems were the result of a Jaguar E-Type barn find that had been sitting too long.
The fact that the car would not idle correctly was due to a deteriorated bypass valve diaphragm. If I remember correctly, the bypass diaphragm regulates airflow at idle. When the engine is cold it allows a different air mixture which changes when the carburetors warm up. The rubber of the diaphragm valve had rotted and became brittle so the diaphragm valve would not close. Since the bypass diaphragm kit was not included in the carburetor rebuild kit I purchased, I had to buy the bypass valve diaphragm kit for my Stromberg carburetors separately.
The overflowing fuel problem was caused by a sticking fuel inlet needle valve. As fuel flows into the fuel reservoir of the Stromberg carburetor, the float rises against the needle in the valve until the valve is closed. If the needle sticks, the fuel keeps flowing. Having been sitting for many years, the needles became dirty. Due to the risk of fire, I replaced them with new ones.