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Mercruiser 57 blowing oil

J

jeffn

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I just bought a 97 32 ft. Maxu

I just bought a 97 32 ft. Maxum w/twin Mercruiser 5.7’s. The engines only have 261 hrs. When I start the boat I noticed a small amount of oil in the water. It appears both engines seem to expel a small amount of oil – assuming thru the exhaust? Is this normal? I’m thinking it is not. What should I look for?
 
Thanks bill - yes I'm sure

Thanks bill - yes I'm sure it's oil. Black in color.
 
"drive oil from a bad seal,eng

"drive oil from a bad seal,engine oil from valve guide seals pooling in a cylinder(s)"
 
Do you notice any oil in the b

Do you notice any oil in the bilge? How often do you have to top up the engine oil? Both the same? Keep in mind NOT to overfill also.

Greg
 
"No oil in the bilge. Starboa

"No oil in the bilge. Starboard engine is a little low. Port engine is full. I notice a little discharge after each engine is started. About half a shot glass full? Engines run fine oil pressure seems good starboard runs a little higher about 75, temp good?"
 
BtDoctur said "oil from va

BtDoctur said "oil from valve guide seals"

Pull the spark plugs and see if one or more of them is oil fouled. Compression test with a teaspoon of engine oil will rule out bad rings. That leaves the BtDoctur's diagnosis.
 
""engines only have 261 hr

""engines only have 261 hrs."

Do the hour meters work? No? Then you have no idea how many hours are really on the engines. Yes? Maybe the meters turned over? Hope not.
uhoh.gif
"
 
"There are alot of if's. I

"There are alot of if's. If oil is getting in the combustion chamber, it will smoke when started. Does it sit for long periods between use?
There is probably some rubber elbows in the exhaust system between the exhaust manifold and outdrive/s. The interior of these rubber elbows can develop a layer of burnt scale from the heat of the exhaust gases and being dried from sitting. What comes out is small amount of black tar like crud. Most noted after sitting for extended periods. If what comes out is engine oil or gear oil, it will leave a sheen on the water and look like oil.
If engine/s does not use excessive amounts of oil and lower unit oil level stays full, everything is probably ok."
 
"I will go with you Bill, it i

"I will go with you Bill, it is more likely it is just a bit of crud from the exaust mixed with a heavy fuel mix on startup.

The fact that it is black tells a bit of a story, I asume you are seeing a stain on the top of the water around the legs, if the stain is local and satin/flat black in colour it is just excess, incompletly burnt fuel and crap from the exaust.

If it is slimy and brown and rapidly spreads from the boat it is oil.
If you were loosing half a shot glass of oil every time you started an engine your engines would be toast by now.

I get a satin/flat type black disscharge every time I start my engines cold, it is caused by the fact I give my throttles a few good pumps before I hit the keys when my engines are cold.

Its nothing to worry about on mine and I think you will be pretty safe as well.

Cheers
Peter C"
 
Thanks Guys - the boat has sat

Thanks Guys - the boat has sat for a while w/o use. The hr meter works and I believe it to be accurate. I do pump the throttles a couple of times before start up and the discharge is black tar like chard. Based on the comments I'm thinking it's nothing to worry about and I will continue to monitor oil levels etc.. Thanks again!
 
"Of course i have to pile on.

"Of course i have to pile on. If you were loosing that kind of engine oil there would be dock neighbors calling you about the blue plume of smoke, the ozone hole above and the rainbow sheen each time you start the boat. Unless you are loosing engine drive oil... relax and enjoy."
 
"MistaHays

"the ozone

"MistaHays

"the ozone hole above and the rainbow sheen each time you start the boat."

I like it, next time I am rafted up next to someone and they fire up their engines with a nice little smoke plume I am going to have to use that one.

Peter C"
 
"Dont forget the benificial by

"Dont forget the benificial by-product, DEAD mosquitoes for 5 miles in all directions!
And sadly, for us on the west coast, the constant toxic waste plume alerts wafting in over the Rocky Mts."
 
Hey thanks just put another 5

Hey thanks just put another 5 hrs on the boat and it's running well. Strangly enough I have not seen any more oil?
 
"Usually in the spring time, m

"Usually in the spring time, mine has sat for 4 months, and to test the performance of the sea water pump, I back the old barge up to the horse water traugh (SP) and dip the lower unit and fire it up and check out the cooling system. What comes out is one or two maybe 3 black honkers. If I do not see a shinny oil sheen, Im happy or happy until the olady sees boat honkers in her precious water traugh.
You will not see anything until you park it for the winter and fire it up next spring."
 
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