Help me get my compressor running! Can anyone help?

I have a Clark Air compressor, it runs off a Honda GX200 petrol engine. Its about 10 years old but has been faultless

It has been in storage for 18 months , I started it very easily today after a bit of fettling and it runs ok continuously (ran it for 20 mins straight with no load). But once I shut the valve down to build pressure it cuts out after 1-2 minutes. It just stops dead, no spluttering. I can restart it pretty much straight away

So far I have cleaned the carb/jet – was gummy and jet partially blocked, now good

Checked air filters – ok

Checked oil levels in the honda motor and in the compressor – all ok

Fresh fuel in tank

Im a bit baffled, I never touch any of the settings so im unsure what might be going on. It sort of feels like something is deliberately cutting the motor, almost like a switch, rather than a fuel blockage as it stops instantly

Does anybody have any clue as to what might be happening?

No matter how well you think you’ve cleaned the carb I’ll bet its dirt in the carb from old petrol that’s causing the problem.

My strimmer is exhibiting almost exactly the same symptoms. It’s currently in bits for a carb rebuild.
But I have no idea what I’m doing, so I’m not sure if that’s the right answer.

When it shuts off, does it release a hiss and ‘unload’ the pipe from the compressor to the air receiver?

If it doesn’t, maybe the pressure relief valve is damaged or stuck down and the engine is simply stalling as the pressure is too great.

Should that happen, they usually don’t start too easily straight away as it is trying to start against pressure, but worth a look at in the circumstances.

How does it knock off air wise?

Is there a failsafe pressure switch? So high pressure kills the ignition

Im looking for a failsafe pressure switch but the tank is not at the working pressure – normally we run at about 6bar and its cutting out between 2 and 4 bar.

I think i need to check the in line filter, under the fuel tank of course, super handy

Thats my point.  If the failsafe is over reading?

+1 for crappy modern petrol. Possibly shove some petrol magic in the tank with some shell v-power. How’s the throttle controlled? Vacuum or speed regulated? Possibly a leak in that as well.

Thats my point.  If the failsafe is over reading?

ah yes, gotcha

Fixed it?

Ha ha, yes!

So for closure I satisfied myself that the compressor wasnt cutting out the motor, then went back and did another carb strup and clean, plus removed the fuel tank to access the inline fuel filter that screws into the bottom of the tank

That seemed to improve things slightly but not completely and the cutting out continued. However, I just had time to push the choke over slightly before stalling, and that coaxed it through the charge cycle. Eventually I reduced the choke slighty each cycle until it ran fine with no choke. So I am assuming it was a partial blockage in the fuel system which gradually cleaned itself out.

So thanks all for the tips and suggestions!