New fuel pump problem

I fitted a new petrol pump to my series 2A to cure a problem with a weak old pump which would not hold petrol up to the carburettor when left standing for more than a day or so. Much sucking was needed on the pipe to get it started.

This has cured the problem but now I have another one! The engine starts and runs fine from cold but when it warms up it goes sick as if it is not getting enough fuel. It doesn't cut out all together but you go kangarooing down the road.

I put the old pump back on and the problem goes away so there is either a fault in the new pump or some incompatability between the new pump and the carb.Possibly too much fuel getting through the needle valve?

Any ideas anyone?

Have you cleaned out your carb?

OSD

That is the next job. Although the fact that the engine will run fine on the old pump tends to indicate that it is not a " **** in the carburettor" problem?