I really think the fuel filter may have an issue but I thought someone else had a similar experience and could shed a little light on the subject. The fuel cutoff is working with no problem. Filter has a little over 200 hrs on it.
The problem again: Mowing thick or thin grass, engine full speed, tank full or low, and make a fast turn right or left (seems worst with left turn) then after 1 or 2 seconds the RPM will drop to at least 1/3 of full RPM then after approximately 1 or maybe 2 seconds the RPM will return to normal. It is not really a problem but it is beginning to be aggravating since the tension pulley on the PTO belts just fell off and I'm ordering parts.