Expert: Everett Peacock - 12/30/2010

Question
QUESTION: My 2005 4.3 ltr MPI Mercruiser is leaking oil into the bilge. I first noticed the gear lube monitor alarm going off and had to fill it several times while operating the boat, I then noticed the bilge had oil in it. What is the likely cause? The motor had a full service only 6 months and 9 hrs of use ago.

ANSWER: the upper seal in the stern drive is bad.. there is a seal behinde the u joints that is leaking.. it lets oil leak in the bilge..

---------- FOLLOW-UP ----------

QUESTION: Thanks Everett. Is this a big job? Does the leg need to come off to fix this. Is there any likelyhood of doing damage to the sterndrive in this period while it leaked out. The gear lube monitor was empty each time i filled it.

Answer

the stern drive must come off.  the u joint assy must be removed to get to the seal.. the seal and pinion nut must be replaced.. You would need a special tool to remove the gland nut holding it gear aasy in place...  There would be no damage the the unit as long as the oil resev. stays full..  keep it full untill it is repaired..