How To: Restore a Morris or keep fit

[Richard Farrant]

Originally Posted by Mike Kelly

Just to add to what Lynn has written

Some of the older Solex carbies are extremely sensitive to fuel inlet pressure- this I think stems from the days when many cars had the petrol tank mounted in the cowl and the fuel gravity fed down. I found this out after I spent a long time fiddling about with a Series 1 Land Rover Solex carby . In the end the problem ( running rich ) was not in the carby , but in the SU electric fuel pump . The pump spec was 1 to 1.5 psi but it was actually around 3 psi and this oversight caused me much grief along with frustration.

Mike,
There were two types of SU pump, high pressure and low pressure. For example a Morris Minor had the pump on the bulkhead and was a low pressure, whereas the Mini had the pump at the back near the tank and was a high pressure as it had to push the fuel further. I guess the delivery pressure at the carb equalled out between the two types. If using a SU pump it pays to check what application it was designed for.

regards, Richard