Originally Posted by teknome
According to my notes the base plate should start moving around 5 inches Hg and reach the full movement at 15 to 17 inches Hg. May be a coding on the diaphragm to denote the start finish and advance

Now that is a great help, thank you so much :-) I'll be out checking first thing on the morning.
Thanks again :-)

Paul

2009 4/4 Sport in Red
2022 Harley Davidson FXLRS Low Rider S
1977 Triumph Stag