Volvo Penta CAV filter thread size

[PabloPicasso]

Does anyone happen to know what the thread is on the air bleed screw of a cav filter for VP MD2040?
Internet suggested M10x1 but it’s not that.

Trying to buy a suitably sized hose barb to connect to it properly rather than bodging a bit of tube into it.
Thanks

You could fit one of those squeezy bulbs in the fuel line instead. Might that be easier?

 

[lustyd]

You could fit one of those squeezy bulbs in the fuel line instead. Might that be easier?

Those things degrade fairly quickly so I’d rather not have one in my fuel line. Sucking the air out is very effective even with my current tube in the hole method, just refining that a little.

 

[lustyd]

Closing this out, I gave in and ordered some thread checkers from Amazon which turned out to be much smaller than they look so storage less of an issue.
Thread turned out to be M10 x 1.5 quite conclusively when using the tools, I checked the various thread types including US (which some sites suggested it was a US thread).

Thanks all for the advice and discussion. I should have known the answer was just buy a new tool, but as I said we're running out of tool room!