Re: Why do Valves Stick?

Posted by Owen_Dyneto On 2013/7/8 17:20:27

If the ambient air during storage is humid enough, it can also enter the engine via the crankcase breather pipe and tailpipe and given long enough storage, potentially rust valve stems. Though my winter storage is relatively short (4 months), I do tie a plastic baggie over the tail pipe(s) and crankcase breather and oil filler cap. Whether it's of any real benefit I don't know but it only takes a couple of minutes to do and undo.

I also want to add emphasis to what Ross says about "old gas" gumming up valve stems - it's a classic cause.