I have a 2150 with about 250 hrs on it. When I engage pto, engine stalls out. Starts and runs fine, new pto switch put in last fall, also new wire harness.
MF GC2400 that replaced retired CC 2518 and retired CC 2160
Check your safety switch for the seat. I have a 2165 that did the same problem, would stall out or not come up to speed. After changing PTO's, PTO switch, I found out the switch under the seat to be bad. I cheated and put a jumper wire on instead of new switch. Maybe this will help for you.