Merc 5.0 V8, burning oil - is it time?

[Tufan]

I have a 1994, 23 Mariah with Merc V8, 5.0, i/o alpha one.<br /><br />I am the second owner of this boat, had it for a long time. Always try to keep in good shape, proper maintenance etc.. Two years ago did a complete over all, replace the out drive with brand new unit, replaced EVERYTHING from water pump to head gaskets with original and new parts... <br /><br />Lately I noticed that she is burning oil - not just a little either, three quarts about a month... (I go out three - four times a week)<br /><br />I am one of those "clean freak" type, bilge is painted white! So there is no leak...<br /><br />I wonder why all of a sudden engine is burning too much oil (or is this too much), Is it time to do a over all again or ???

 

[ron7000]

Re: Merc 5.0 V8, burning oil - is it time?

how many hours on the motor? do a compression check. Low #'s may mean poor piston ring seal. Check the spark plugs, dark black, soot covered electrodes means you're burning oil. Checking with a vacuum guage at idle may also help, if the guage doesn't hold steady then valve seals may be gone and you're getting oil into the combustion chamber from there. If all that checks out, then are you loosing oil into the coolant side of the motor? Is there an oil cooler, or do you notice oil in the water around the boat?