With the recirc' through the orfice in the intake runner, there's an increase in crankcase pressure that develops with the varying rpm / blowby... the GF40 with the gas walbro carb was affected by the increase pressure on the fuel pump diaphragm, which affected throttle transition / response... The idea is sound, just not well executed... try blocking the PCV valve on your vehicle's engine and see what happens with oil forced out the crankcase seals... if they want to implement a recirc' PCV system on a model engine, there needs to be a means to scavenge the crankcase, but that won't work well with the walbro fuel pump system... there's no need to over complicate things with such a small displacement model engine.