I have a 1990 Donzi Levante 300 with twin 5.7 OMC/Cobra's, 220 hrs on each engine. When I winterized the boat last fall I had the dreaded milky oil in the starboard outdrive. This is the first time I've encountered this ever. A little history, last summer I checked the oil level and noticed the plastic (or Nylon) dipstick gasket was broken so I replaced it with the part number listed for a 1990 OMC cobra, which was an o-ring. Well, when I found the milky oil I also found that the dipstick was loose due to the o-ring. So, I suspect this was the culprit. I want the flush out the milky oil prior to pressure checking and if no problem is found, refilling it. Can I remove the top housing cover, remove lower drain plug, and flush with either diesel fuel or some other fluid prior to refilling with oil. I would also replace the cover o-ring, and the dipstick o-ring with a different gasket.