Hi folks. I bought a walbro wt-38b carburetor to replace the zama c1q-s63a carb that came stock on the stihl fs-85 I bought 7 or 8 years ago. (The machine over the past couple of years has gotten progressively worse starting and running. This year it finally became untenable, and basically wouldn't yield to *any* carburetor adjustments I made. Fuel also began leaking from the carb itself.) The walbro carb doesn't have a primer bulb on it; the zama does. Since the walbro didn't come with a bulb, is it intended to operate without one? Would it hurt anything to add one? One reason I ask is because the fs-85 fuel tank has two fuel line ports drilled into it: one for the main fuel feed line to pass through, and another for the primer bulb vent line to pass through (I guess that's what it's called). If I don't use a primer bulb on the walbro carb, I have to plug one of those tank ports, since, in the absence of a primer bulb, there's no place to hook up the vent line that passes through it. If I add a primer bulb to the walbro, then I have a place to hook up the line. Any guidance appreciated.