Hope you guys don't mind this question about my jcb?
Having had my 1972 jcb with the 4cly leyland engine for a while, I have looked at the poor starting. The previous owner had used ether as a cold start

I have cleaned all the fuel lines, new filters, flushed out the lift pump ( the filter screen is missing) . The rack moves freely from stop to max fuel.
I did press the cold start button once and it fired up like a major

The cold start button does not always work correctly tho , part throttle, engine stop in, and the button won't go in now!
It is a simms minimec similar to the majors, how easy is it to rectify the cold start button problem, does the pump need to be removed from the engine? How easy is it to retime, the pump bolts flush to the block.
If any one could post a picture of the cold start section of the pump that would be fantastic.