[NSRCA-discussion] Minor YS issue solved

[Bob Kane]

I was having some minor YS issues prior to and into the NATS.  The midrange on my very reliable but several seasons old 160DZ was weak, but top end power was good as was the idle. This year I had replaced the rear main bearing and more recently the front bearing and seal. I tried adjusting the pump but it seemed it was already the optimum position.  I was also getting some oil residue in the cowl area. This is normally a "dry" engine without much mess in the cowl.  I replaced the rocker cover gasket just prior to leaving for the NATS thinking it might be the problem, the o-rings on the pushrod cover looked ok. At the NATS I soon discovered the new gasket did not solve the oil problem but I just lived with it for the week.  Upon returing home from the NATS, I pulled the head off and found the source of the leaking.  The black o-rings that support the fuel pump were cut/worn. These are hidden by the pump so they canot be inspected without oulling the head.
  A new set of o-rings and the oil leak is gone, and the mid range transition is back to normal.  I had not removed them during the prior bearing replacements, I just assumed they were ok. Lesson learned.

 Bob Kane
getterflash at yahoo.com