My powerwasher and my one push mower have no throttle adjustment. The powerwasher has a 6.5 horse honda and the push mower has a 4.5 hp briggs. I know the manufacturers probably did this so save money but it really doesnt make any sense to me. I have thought of converting them to an adjustable throttle but thought it may not be so good on the preuusure washer. I know that when under a load, the engine doenst run at full throttle. Would the pump not be able to handle the speed? I just cant figure it for the mower though. I see no reason as to why Im not able to control my throttle. I was mowing some knee high grass today and the damn thing kept bogging down on me. I had to pull my old 3.5 horse briggs murray out with an adjustable throttle. I cranked it up and that thing ate the grass with ease. Has anyone converted to adjustable throttles?