help needed with cold start device on 454 and 574

I have a 454 and 574 both with the same cold start device. The 454 always starts easily (don"t they all) so I never bothered looking at the cold start but the 574 is a reluctant starter (arn"t they all) and is a new to me so I am trying to get the cold start working. The device is located part in the air manifold and part on the battery box. The unit on the battery box seems to be little more than a pipe connection box with a glass sight bulb on the top. it takes a feed from the injector return pipe and continues on with a pipe to a T piece joining a pipe from the injector pump, then onwards to the fuel tank, there is a third pipe to the air manifold unit. The unit in the air manifold is a heater coil with a nozzel in the center fed from the third pipe from the battery box unit.
The function seems obvious, the heater coil glows red hot and fuel from the return pipe sprays on to the heater coil and so provideds encouragement to start.
The questions are what stops the fuel constantly flowing on to the coil and into the air manifold. Is the manifold unit repairable / dismantalable and are these units "industary standard" or IH special parts?

GOOGLE "THERMOSTART" and you'll get LOTS of hits to pages with photos and diagrams and explanations of how they work. Ford commonly used them and certain Cummins engines, as well.