TEF Starting excess fuel button

[Cornwalltef]

New to the CAV pump on the TEF20. Mine is a real pain to start always needing a good dose of Kigas. If I press the excess fuel button (with stop handle in start position) and speed lever about half way, it doesn't click just springs out again. Any ideas? As I understand it, the spring on the diaphragm end pushes the rack more to fuel end (away from governor end) prior to start as no vacuum. I'm guessing the excess fuel button allows the rack to move more fully to the fuel position by a hole drilled in the end of the rack and a pin that will then fit into this hole when the excess fuel button is pressed? On starting, the vacuum overcomes the spring pressure and pulls the rack back to no fuel end and excess fuel pin pops back out...so how does the rack then move more to fuel end if the hole and pin no longer align?

Any help much appreciated!

[Sandy.]

Hi
In the normal run position the end of the rack comes in contact with the end of a pin, when you push the excess fuel button in it moves the pin sideways to allow the rack to move to the excess fuel position. 2 Things to check, 1. disconnect the stop rod at the pump and make sure it is going all the way back and not being held off the run stop. 2. Remove the side plate from the side of the pump held with 2 screws, then while watching the rack press the excess fuel button and watch for any movement of the rack.
Sandy.

[Cornwalltef]

Thanks Sandy, had a look at the rack with pump inspection plate removed. Looks like the rack will go all the way to the excess fuel position so I'm thinking the pin is missing...