Ok, 07 650i, set for a few months during off season. Started up and it runs like hammered u know what. Thought maybe it was the gas so I added sta-bil and it did not help. Took the air filter off and looked at the slides on the carbs, they seem to be working fine, however there is a tremendous amount of vibration when I give it throttle (normal??). This machine has always from day one been a hard starter, choke for about 45 seconds while trying to start and leave choke on for about 3 minutes until it warms up. No problem after that.
How can a machine run so good at the end of last season and so bad at the start of this season???? Belt is fine and is not in limp mode. It will run and run hard just doesn't sound very good with pop pop, spit spit and occasional small backfire thru carb(s).
Does anyone think it is just bad gas?? Should I be running 93 octane in the unit?? Any advise is appreciated. I really don't think it is the jets or valves because it is almost like it happened overnight.
Thx for lookin.