timing/ governor problems.
 

I'm working on a 12 valve p pump. It won't rev past 2000rpm and sputters at 2000 rpm. Runs fine up to there. Also I was told that adjusting the AFC didn't have any effect. Could it be a messed up governor or slipped timing. Or both. Really stumped on this one. I tried tightening up the gov but it didn't help. Any help is appreciated.