Oil on top of engine - OMC 5.0 Cobra

[thewooddogg]

Hello,

I've got oil on the top of engine block after running the boat for a full day. Not a lot, but just little pools of it in the depressions in the block. Is this something to be worried about? I normally just dab it up with a rag and before I go out. The bottom of the carb does seem a little wet. Any ideas? (i'm a boat newbie, so be nice please!)

Also, the first time I started the boat yesterday, I put it in reverse and bunch of white smoke came out the back... seemed like it was just exhaust, and didn't happen again the rest of the day.. but it didn't happen the last 3 times I took the boat out this year and it was kind of embarassing. Any ideas?

The only other problem I have is has a pulsating idle. When idling, the engine will rev up and down a bit, and typically it'll die (especially when cold). But it will start right up again every time and continue to pulsate at idle. Any ideas on all of this or first steps I should take?

 

[HT32BSX115]

Re: Oil on top of engine - OMC 5.0 Cobra

Oil on the top is usually from a leaking valve cover gasket or leaking oil filter/oil line near the top of the engine.

Oil leaks are messy but usually don't hurt anything unless some overzealous boat cop sees you with your bilge pump on and you're pumping oily water overboard.....then it gets pretty bad (for you)

White "smoke" is probably steam. But it's hard to tell without a picture.

It's possible that your raw water pump is not pumping much water at idle and the exhaust system is getting pretty hot before much water is flowing. Then when the water hits it you see some steam.

Pulsating idle? Can't say not knowing if it's carbed, fuel injected, electronic ignition model number, year, serial number etc. Put that stuff in your signature and it will be easier for the more knowledgeable people here to answer your questions without having to ask for all that pertinent info



Cheers,



Rick

 

[87 bayliner]

Re: Oil on top of engine - OMC 5.0 Cobra

the bolts holding the intake manifold down can be the culprit. the ones toward the middle of the manifold their holes open straight in to oil containing areas of the engine.

clean out the oil, loosen the leaking bolts one at a time and put a ring of silicon gasket maker (permatex grey is good) under the bolt head and re torque the bolt.
]
or the valve cover...


j

 

[WaterWitch2]

Re: Oil on top of engine - OMC 5.0 Cobra

the bolts holding the intake manifold down can be the culprit. the ones toward the middle of the manifold their holes open straight in to oil containing areas of the engine.

clean out the oil, loosen the leaking bolts one at a time and put a ring of silicon gasket maker (permatex grey is good) under the bolt head and re torque the bolt.
]
or the valve cover...


j

I've had car engines do the same thing and fixed them the same way.

 

[thewooddogg]

Re: Oil on top of engine - OMC 5.0 Cobra

Thanks for all the replies! I'll be adding the boat info to my signature once I write it all down.

The boat is a 92 Four Winns 190 Horizon with a 5.0 OMC Cobra. It has a Holley carb on the top of it. I'll see if I can get the serial numbers and what not later today.

Sounds like the oil thing isn't much of a problem... as long as it's not dangerous I'm ok with a little oil on top.

The smoke issue: the white smoke had a definite exhaust like smell to it. I couldn't tell if it was burning oil or just the exhaust coming up... This only happened on the first or second time I went in reverse on the boat. It didn't happen again the rest of the day.