Mine has exactly that but you have to be careful if you hold down the thumb screw they carry on producing, I pump my air pig up to a higher pressure by briefly holding it to get it to 180psi make the amps go to about 15 but its ok for a short burstThe governors usually found on these were like this one
DO NOT RUN THIS AS IT IS IT WILL KILL SOMEONE !!! with that size engine it will just keep making air, up to a ridiculous pressure
I have got one these ac10's exactly the same but with an electric motor, but your pipe off the head is not going into the reservoir it will blow any plastic pipe off it should have a coil of cooler pipe behind the fan/flywheel,from the head then into the res where it then senses the pressure and unloads it through the unloader valves in the head. the motor just keeps running all day. Good for petrol diesel app. or running off a genny.
But it senses the pressure from the the u shape res so if it is not going into it,if you just run from the pipe off the head directly into your big res. it can't 'see' the pressure it is building up!and stop it making air.
The feed for the regulator is the thin pipe from the u shaped res.
It wants the proper cooler pipe connecting back up then fill the big tank from the u shaped res.
That way the thing is safe both mobile or static dosnt matter that it is used for blasting there are a lot of dead people whos last words were 'oh I will remember to shut it off'!!
Will take a pic tomorrow morning and post itThe hoerbiger pilot valve that's is fitted to it is it like this http://www.hoerbiger.pl/pdf/ARC-T.pdf
If its similar then you will be ok.
Is this so I don't overspeed the pump knows it rated at 10cfm but will be more than that with this motor, mind you it must of been made with this motorWhat kind of RPM does the compressor spin at when running, do you have access to a tachometer to check it.