can't figure this switch out

[Mrclean667]

read some manuels on the M54 and figured most things out but this switch I have no idea what it does. please help
The switch to the right of the throttle pull handle. What it does?

 

[FormerNewMVGuy]

You could try tracing the wires connected to it. See where you end up.

 

[Mrclean667]

I hear a whinning sound (mechanical sound) when depressed. It is spring loaded, dead man switch, it automatically returns to the off position when released

 

[hklvette]

It looks like the type of switch used for the M35's intake flame heater. Perhaps some sort of cold-start assist?

edit: Based on the noise you hear, almost definitely the flame-heater switch.

 

[Warthog]

From the TM 9-2320-211-10 Operators Manual, page 2-4, it is item #2

Manifold heater switch controls operation of the manifold heater and is used to facilitate
starting and warmup of a cold engine when temperatures are below +20º F.

 

[jatonka]

It is the manifold heat switch. Better if you don't actuate it until the engine is cranking over or it could send raw fuel into the intake and into the combustion chamber, leading to possible Hydro-Lock. Not a good thing