You absolutely can try it. The normal advise is that the WT456 is the carb of choice because it has a special helper spring inside the pump cover that was originally intended for 4 stroke pulse, taken from the intake manifold. But that carb from Walbro hasn't been available for about 3 years now. I've been using a standard 2 stroke carb on a Stihl 32cc 4 stroke 4-mix, and have gotten pretty good results. But the intake has some innovative porting going on that might be helpling it. I haven't messed with that engine for about 3 months now, so I'll have to refresh my memory if that porting is helping. Normally, the pulse, for a 4 stroke, would switch from the crankcase (2 stroke) to the intake manifold. But, if memory serves, the Stihl is still (ha ha) taken from the crank case. I'll look and let you know. The easiest thing to do is to just try it. But hook it up to the intake, NOT the crankcase, if you're converting a glo 4 stroke like Saito. The reason is the crankcase NEEDS to breath on a 4 stroke.