I know this will come as a huge disappointment to many people but we can now put this thread to rest.
Ran the mower yesterday for a long time, no issues at all. The problem was undoubtedly the valve stem seals that are pressed into the cylinder head. They were worn and allowing air to be pushed into the crankcase causing excessive pressure buildup in the crankcase resulting in oil being forced from the crankcase up into the valve cover breather and through the rubber vent tube into the air cleaner then into the carb where it was sucked into the intake and the oil was burning in spurts in the combustion chamber causing intermittent puffs of blue smoke from the exhaust. The leak in the seals was so slight the mower had to run for about 30 minutes before enough pressure built up to cause the problem to start, so for the first 30 minutes it ran like a champ.
I know this thread has been a pain but I appreciate everyone who hung in there to help me diagnose and fix this problem.
Ran the mower yesterday for a long time, no issues at all. The problem was undoubtedly the valve stem seals that are pressed into the cylinder head. They were worn and allowing air to be pushed into the crankcase causing excessive pressure buildup in the crankcase resulting in oil being forced from the crankcase up into the valve cover breather and through the rubber vent tube into the air cleaner then into the carb where it was sucked into the intake and the oil was burning in spurts in the combustion chamber causing intermittent puffs of blue smoke from the exhaust. The leak in the seals was so slight the mower had to run for about 30 minutes before enough pressure built up to cause the problem to start, so for the first 30 minutes it ran like a champ.
I know this thread has been a pain but I appreciate everyone who hung in there to help me diagnose and fix this problem.
