[REPORTED] Priming pump not required for engine startup?

[Slegawsky]

Should we atomize some petrol inside 14 cylinders in order to start the BMW?

Hard to find any substantial piece of historical evidence to back this up but the yellow thingy is there.

 

Edit: 109K-4 seems to have a primer too.

[NineLine]

I just tested, at -6C you need to prime 2 pumps, that doesn't seem to be enough, same with 10C no pumps required. I have sent for review with the team. Thanks!

[MAD-MM]

It took me while to find something, but Photo in the starting Post is from the maintenance Manual (Aircraft Overview). General overview of the Aircraft for the Ground crew for Inspection where you can find everywhere in there Internet. But in there is no written Pilot Instruction in it how to use the Aircraft or this case how you start up the A8 or even when to use the Primer Pump. In German the Pilot Manual is called Operating Instructions (Bedienvorschrift). What is basicly hard to come by. Basicly the same for K4 or and A8, the Engines are Fuel Injected dont require ignitable mixture like the Merlin for the Start up to soak up the Fuel from the Carburetor. Only thing is Fuel start to Condense on Piston Walls at low Temprature, there for is the Priming Pump in the A8 as the K4 to get a ignitable Fuel Mixture at low Temp.

After some thoughts where to search came across BMW 801 Engine Data Card with Operating Instructions:

Bellow 5 Degrees 2-4 Priming and under 15 Degrees 6 Times, little bit low what NineLine reported, but Priming a Engine is not exact sience

 

[Yo-Yo]

Absolutely. Depends on fuel type. More or less volatile. By the way, I asked Erich Brunotte if he used primer, and he said that never in 109 and both 190.