I have a model 31C707 Briggs and Stratton 16.5 hp engine that has a gallop issue. I rebuilt the carburetor replacing the float needle valve and cleaning the carburetor body. I can get the engine to run smooth at idle, but when the RPM's are increased I need to close the choke part way and the engine gallops. I feel it may be a fuel delivery issue, but am stumped as to where the restriction may be.