Sorry for the delayed reply.
There is no cable in the primer hole. It is a hand primer pump as shown in this picture (red arrow).
It has a locking ring (red arrow in next picture) that you must pull out to use the primer. It prevents unintended priming.
This next picture shows the locking ring released and the primer out sucking gas in to the pump. It gets pushed in and out to transfer fuel to nozzles on the intake manifold of the engine.
This next picture shows where all the various supply fuel lines go. If the text is too small, PM me your email and I will send you hi-res pictures.
This picture shows the fuel line coming from the primer pump, the location of the nozzles, etc.
Note that I think this is a Military Standard (MS) primer pump kit. It looks to be exactly like the one on my M38A1 (1955). I've seen these kits listed on eBay. The army jeep folks in the US also used to sell complete kits - I don't know of availability now. Here is a picture of the kit I obtained off the internet.
If my genny has been sitting for more than a few months, the primer will allow me to start it right up without having to crank on the starter forever. This is good because parts for the starter are very, very hard to find and very, very expensive.
Please let me know if you need any more pictures or have other questions.
Can you please post some pics of the genny that is being restored?
Al Jones
Brookings, SD