I have to shut the fuel switch off on my '94 Heritage at night because it pushes fuel out of the overflow tube. I have had the float bowl removed, cleaned and the float adjusted three times. I have been told by the mechanic that perhaps the seat for the float needle valve is shot and there is no way to replace it without buying a new carb. Any suggestions?

 

It is good practice to shut the fuel off at all times! The leak is due to the shut-off valve not working correctly. If your mechanic has used a new float needle 27886-78A and that doesn't work, then his diagnosis sounds OK, which is to say the seat the valve sits against, to shut off fuel flow, is shot. There are plenty of secondhand carbs around, which if you buy a secondhand low mileage one, should cure your problem.

An alternative is to go to this item on Ebay and contact the seller. He may be able to replace your damaged seal: #221129205737, as part of a complete overhaul.