Buddy had the Rave seals changed on his 19 850. Now that we listen to it closely there is an occasional knock, tick, ping that sounds like it's coming from the PTO side Rave area. It seems to occur when the engine has that ever so slight 2 stroke stumble. If you just hold pressure on the Rave stem nut or the bar between the valves the noise stops. Anybody hear this? Is it normal? He's trying to get in to see the dealer but maybe someone knows what this is?