912ULS carb overflowing

The occasional debris flecks following a new build or fuel hose replacement is not uncommon and normally stops after a bowl cleaning or two. But metal debris found in a new Bing float bowl (are these new Bings?) And now both carbs now dripping? Interesting. You may have two issues going on. Both overflowing may be the inadvertent entry of ram air- are you using an air box or just filters? How are the carb vent lines routed? It will help to know if any debris is found in the second carb bowl, but these carbs can drool fuel with no debris to be found when one drops the bowl- this has happened to me. Just dropping the bowl will flush any tiny fleck of debris wedged at the tip of the viton seal, and as the viton seal lowers along with the floats you may never see a tiny speck of debris as it falls away with the fuel.
First I’ve ever heard of metal debris sitting in the bottom of a float bowl. 
If I found any metal debris in the bottom of a float bowl of a new Rotax Bing I’d submit a CSIR to Rotax.

Hi.

Thank you for your thoughts.

Routing of Carb vent lines have not been modified and had been working fine with the old engine.

CSIR had been filed after the first occurrence.

We will do a new CSIR now and will see what will happen.

As Jim suggests, this almost has to be debris in the fuel line after the last filter. You mentioned these hoses were replaced, have you disconnected these and flushed them out into a clear container?  

Hi all:

All 9 series engines are run on a dyno for hot test at the factory for 30 to 45 mins.  The original carburetors are run and the performance is logged and is verification of it meeting the minimum standards.  In that respect the original carburetors were fine.  Storage while in shipment and waiting for installation at some wearhouse is limited to a period of time as defined by Rotax in their documents.  Contamination from  fuel line debris or other issues with your fuel system are not warranty.  If the issue is contamination from old fuel your service provider should be able to fix that, there is no reason not to know what to look at as this is rather simple.  What you need to find out is how old is this engine?  How many months has this been sitting without running?  At the very worst the inlet needle and perhaps the idle and main jet would need replacement.  Metal is something within you fuel system and needs investigating.  Even installing brand new carburetors will not solve contamination from another part of your fuel system.

Cheers

Thanks everyone.

To clarify:

This new engine was installed and tested very shortly after we got it - that is when the carbs overflowed the first time.

Just before that, we had also replaced all filters and the fuel lines. During installation also filled in new fresh fuel.
The last filter is in the Gascolator - and from there only one new hose goes to the ROTAX fuel pump. All from there is new orange fuel lines factory mounted by ROTAX.

Then carbs were gone for inspection and we tried them again one week after re-installation. So no long time sitting around either. After the first set of problems, we have flushed all fuel lines again into fine filters - and nothing was discovered.