Re: Help needed with slight smoking issue after recent fe390 rebuild
Common cause of blowback / back pressure can be caused by restriction on engine breathing .Faulty PCV valve or restriction on hoses . sometimes collapsing under load .Faulty valve stem oil seals usually show up when engine hot , left to idle for a few mins. and then revved up is when you get a puff of blue smoke at rear . When really bad , you can see it when stop / starting in traffic .Also oil tends to carbon up on valves .
Never, never, never give up.