Hi Diablo,
I am not sure at what the optimum ground speed for your machine is, nor what RPM the Briggs is comfortable with for average lawn mowing.....with my Scotty, my Honda runs at full throttle (governed of course) and combined with the hair-triggered clutch, I can vary the ground speed to my liking. With your set-up however, it seems the PTO pulley diameter is all important.

Your machine had a 3" pulley fitted and was to fast, the 2.5 may be a trifle slow....maybe a 2.75" may be the answer...and you could consequently reduce the engine RPM accordingly to achieve the ground speed you are comfortable with. wink
Thanks for posting your test results. grin
cheers

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin