OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Quantum Briggs and Stratton Fuel Tank Leak at Seam

The flux was the culprit. Been there done that on other tanks except I prefer to using air pressure and a water bath or soapy water sprayed all over for testing.

Also sounds you used the soft silver solder and not the hard stuff. The hard silver solder takes an ACE/OX torch to get hot enough to work on large pieces.