Hi Andrew

I bought a 1964 one of these back in the 70's to restore. Ours had been standing about 4 years and was only firing on a few cylinders when we got it going

From memory we just stripped on the bench, cleaned and put back together, was just stuck up with dried old fuel gunk

Give it a go if your brave enough , just a straight forward mechanical pump, nothing sinister, just make sure its timed up before removal

Peter