Refitting a Pierburg

[fuzzy]

I’ve replaced my Weber 34 DAT carb which was fitted to 1.9 DG when I got it. I bought a used Pierburg from another DG engine and had the carb fully stripped and rebuilt.

The Pierburg is now fitted but a couple of seconds after starting the engine petrol is coming out of small brass colour gauze which I have highlighted in the photo.



I have checked that there no blockages in the return line and petrol is flowing back OK so I was wondering if the fuel pressure is now too high like it was changed for the Webber being put on. The fuel pump is stamped as a Pierburg pump so I am assuming its original before the Weber was fitted by a previous owner.

So could it be the fuel pressure is too high, how can I check that and is there anything I can do.

Thanks for looking
Neil

[bigherb]

That's the vent for the float chamber. Most probably the float valve is stuck/ not seating properly or the float is stuck/punctured incorrectly fitted.

[fuzzy]

Thanks Bigherb, that’s really helpful. I’ll get that checked out.

[fuzzy]

I’ve removed the carb to check over the float and all seams OK, it’s not punctured or sticking, that I can tell, but that’s not to say it was sticking when I originally tested it. I’ve not refitted it back on yet to test it again but when speaking to the company who refurbished it they ask me if it could be that the fuel pressure was too high.

Has anyone experienced any issues like that when going back to a standard carb?

Thanks

[bigherb]

If it has the original pump then the pressure should be between 0.2-0.3 bar (2.9-4.3psi). Hold the carb upside down you shouldn't be able to blow into the carb through the fuel inlet.