Classic/Antique Car Repair: rolls royce silver shadow 2 1978, rolls royce silver shadow, royce silver shadow

Question
Hi recently had fuel pump failer on a1978 silver shadow 2,6750cc engine.we had a mechanic change the pump and put a replacement universal pump which replaced the su`s for xj,the e type jag.Now the vehicle starts and wil run delivers fuel fine to the carbs,but i have to switch off amediately as the full flows fast from the one of the carbs,why is this?,does the original su pump have a pressure realise valve?,or is the float stuck wide open or something?please help this car is so lovely but no one can help.

Answer
Hello Danny, There is most certainly an issue with your carburettors, stuck needle and seat or bad float. these units are fairly straight forward but alas in this age of fuel injection most mechanics are unfamiliar with carburettors let alone English S.U models. usually when these units reach this point it is wise to R&R both and make all necessary adjustments. running the car in this condition is also very detrimental to the engine due to improperly metered fuel entering four the the cylinders. If you cannot locate a competent British car specialist in your area the next best option is to have the complete plenum with both carburettors removed and sent to a specialist. the consequence of a poorly done job is burned valves or scored cylinder walls which in it's current condition the latter is happening now due to fuel washing the oil film from the piston rings to cylinder wall surfaces. May I ask what state you are located in?