Cobbling can be fun Red, but a plastic tube inside a carburetor isn't likely to last very long (the few plastics that are petrol resistant tend to be expensive), so you don't have much chance of it working for long. However if it stops, or begins to run badly, you should be able to go straight to the source of the problem.
Getting bits for old mowers requires either a lot of luck, or being plugged into a network. A number of Outdoorking members are often able to help each other with bits, if you post something in the Wanted section.
