I have a 180.b that has a vibration/pulsation that occurs regularly. I took it to a local dealer, they checked to make sure valves on the engine were adjusted properly, did a compression check, checked motor mounts, and did a few other various things. Everything checked out ok. $1000 later and it is still doing it. The machine has 890 hrs on it. It seems to come and go, runs fine and starts good. It doesn't seem to lose any power when this occurs either. No smoke. Any ideas? I am new to this site, hopefully you guys can think of something.