1984 mercruiser 3.0 should we run awais a hair dryer when taking oil fill off

bouncefactor

Cadet
Joined
May 7, 2013
Messages
13
First my son and I know auto engines fairly well but want a boat and may have screwed up. Put a 200 deposit on an 84 Sea Ray today with 3.0 mercruiser. The engine was winterized and it just came out of storage or so we were told and all clues appear to that being true. It was fogged when put away and on start up it smoked for a few seconds. Smoke mostly stopped except for a little white smoke maybe steam(not blue or black). Engine was rebuilt in 2000 by reputable shop. Was bored .020 over heads were milled and valve job done. Rods were reused obviously new bearings crank was polished not turned. Supposedly there is like 200 hours since rebuild(they added an hours gauge).

Ok so why i am concerned. Pull the oil fill off and it is like a hand dryer in a public restroom. Now this is where our auto knowledge may have hurt us. With that kind of blow by I would expect to see some smoke coming out as in an iron duke 2.5 auto engine with worn wings you would see combustion smoke with bad blowby. Also blue smoke from exhaust when it is gunned. Didnt see either. We then checked compression. We idled engine for about 5 mins varying from 800 to 2000 on muffs. Gauges seemed to work and it didnt get hot and was not mixing water and oil(no chocolate milk or oil getting higher). Oil pressure was good but does not tell anything about bore wear. Checked compression using a cheapy harbor freight gauge what we had. Jumped to 50-60 range on first crank and all cylinders were in the 110+-120+ range after 3-5 cranks.I had him stop when it jumped past 110 after 1st cylinder as that was in spec. of the 10% rule. We did not do a "wet" test. Should we be worried.
 
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achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1984 mercruiser 3.0 should we run awais a hair dryer when taking oil fill off

... Should we be worried.

I see no reason to be worried, just yet... I have seen more than one of those 3 litre engines do exactly what you describe. Make sure you do a water test, and run around for a good 30 minutes. If you still have the 'public restroom dryer' effect, then get worried.... While on your water test, make sure to run the engine at wide open, and note the engine revs. Needs to be in the 4200-4600 range (and I prefer to see them up towards the top end of that)....

Good luck.

Chris.....
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
Re: 1984 mercruiser 3.0 should we run awais a hair dryer when taking oil fill off

Try the compession test after getting it warm.
 
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