old kohler generator

[Belliure 50]

Howdy All, posting this as I'm drawing blanks elsewhere on the interwebs.
I have a circa 1987 4kva kohler genset driven by a yanmar 2GM20F. My project list has finally brought me to getting it going again after sitting idle for 10+ years.

The problem I have is as follows. There is a solenoid attached to the fuel cutoff, that activates when I press the momentary start switch. But as soon as the yanmar coughs into life and you release the switch, the solenoid deactivates and cuts off the fuel.
I'm trying understand what/how exactly is supposed to keep the solenoid energised so the little yanmar will run after the momentary start switch is released.
As far as I can tell there have been no modifications to the starting system. It's a simple momentary push to start, push to stop rocker switch on top of the genset.
Appreciate any advise.

[skipperpete]

The solenoid operates the engine shutdown when a fault is detected in the protection system, usually high coolant temp, low oil pressure, high mixer elbow temp and occasionally alternator fail. When you first start the engine the oil pressure is zero so the protection system is actively in shutdown mode and the push button bypasses the shutdown command from the oil pressure sender until a pressure is detected and the button can be released. The circuit is usually a series ground loop but since you have a kohler there’s also the possibility that the “run” terminal on the solenoid is faulty…. The “pull in” terminal usually gets its power from the start solenoid and the moment cranking stops the pull in is inactivated and the hold in coil keeps the engine running.