Re: Misfire issue???

Posted by Fish'n Jim On 2014/11/30 19:11:02

Is it backing thru the carb, missing/not firing on all 8, or backfiring out the exhaust?
"Lifters" are more prone to stick than valves and valve stay open. They have a shorter guide and take the slapping abuse from the cam especially if not lashed correctly. Valves have springs to close them. The valve seal surface is prone to wear and heat damage and stem warpage but usually only if it's over revved or heated or hit by the piston but that can't happen on an L. The valves are not in/above the combustion chamber per se. A large build up of carbon on the exhaust valve stem can cause aimilar problems, and why I don't like to add oily things to the gas. The "coking reaction" is well known in petrochemical industry. Correcting these are what used to call for a "valve job."
When was last oil change?
How long since last start? More than a week or cold climate?
Do you rev it up when you start cold or allow to warm up?
All these put the valve train at stress. The lack of oil at start causes most engine wear damage.