Reply To: Johnson QD fuel consumption

[Don]

Again, the larger engine pictured in that article has the external cover with the drain valves inside.  The QD models don’t have this style cover set up.  The drain valve is on the reed plate and directs the excess puddled fuel/oil to an internal passage inside the front crankcase cover that directs the puddled fuel down into the exhaust housing.  There is no easy way to redirect the puddled fuel/oil on the QD series powerheads like there is on the larger engine pictured in the article.  I suppose you could remove the powerhead, then drill a hole perpendicular to the tiny drain passage, then adding the nipple to recapture the excess puddled fuel, while blocking off the actual vertical drain hole in the front crankcase cover.  But, this would be quite the delicate procedure to get everything right for this experiment.

These QD series engined don’t have any of the “recirc features/lines” like those used in the 22CI engines in the early 70s either.