As the tank is vented a loose return barb will not be an issue as far as running goes.
But you would want to repair it as it could be a major problem if the barb pops out of the fitting on the trail and sprays fuel all over the engine compartment.
Converting Walbro to Mikuni on JDX 4
Re: Converting Walbro to Mikuni on JDX 4
Todd Schrupp
Milbank SD
Milbank SD