David J unless you have worn metal parts such as bushings, metering needle, jet there really is not too much inside the
Stombergs. My main troubles with them over the years has been leaking floats sinking and vacuum leak at one of the manifold system gaskets. Also if sits for awhile I have had the float needle stick. A tap on the carb body with hammer can sometimes free it when this happens. You might pull the bowl off the bottom of the carbs and unsnap the floats and shake them to see if any fuel inside. I have replaced 4 floats in the past 15 years. I have pulled my carbs off a couple of times as a set still hooked together on the throttle shaft and pulled the bottoms and tops off and cleaned them out and replaced the rubber stuff, set the float level and put them back together pretty easy. Might be worth a shot before sending to a shop. My 2 cents
David Barnes
68 E-Type FHC