Mine developed the puff at start up, then all the time at idle and nuetral revs. Turned out water had been dripping into head from a leak at the exhaust riser gasket. Damaged valve and guide. Never found full extent of damage becuase I sold the boat while under repair.

i will find out. I talked to him yesterday and he said he did not use valve seals on either motor.

i had a problem with the the exhaust valve sticking from exhaust gas temperature. The machine shop told me to take all the seals of run it like that. Mine also puts of a small puff of smoke on start up. He said that 75% of race cars dont have the seals on their motors.

Interesting...........

Intakes should still have seals. Intake manifold vacume will pull oil from the valve cover area if you don't. This can be a lot of oil as the engine ages and wears a bit. Exhausts don't have any vacume so they tend to get starved for oil actually.

ditto what patriyacht said