milky oil

I have a 79 mercruiser 140, on my outing last night for some fish, I noticed milky oil covering the engine when I lifted up the doghouse. it was on my valve cover and I suspect that it came out from my oil cap. I have only had this boat for 2 seasons now and am wondering if anyone can share any light as to what the problem may be. This is my first I/O and I am thinking along the lines of a car engine that I either have a problem with my head gasket or my head. I immediately shut the engine down. I started it back up after I cleaned it up a bit and tried to look for any spots where it could be coming from, but nothing showed up and it was idling normally. Any ideas?

 

You are getting water in the oil internally. There are people here that can give you a better idea of where it's coming from than I. But I wouldn't run it untill it's fixed.

 

You"ve got water in your engine! In my experience this is almost always the exhoust manifolds. Wait to see what someone else posts. Check the dipstick to see if there is any oil in the crankcase (and there probably is) drain all oil out of the engine and flush it out with diesel fuel and pickle, if you dont have time to do this in the near (ASAP) future at least pickle the entire engine in diesel. the diesel will displace the water from the bearings and all other moving parts, spray valvetrain with diesel in a squirt bottle and pull spark plugs and fill the cylinders with diesel as well. After you have done this you can get along with finding the cause, getting parts and replacing. The motor is protected from corosion.


Reguardless of what type of cooling system this boat has(raw water/heat exchanger)the raw water is expelled through the the exhust manifold on the way out. There is a water jacket surrounding a header (so to speak) its purpose is to cool the manifold casting. After the water circulates the manifold it is introduced to the exhaust at the manifolds aft end to cool exhaust plumbing. It is when this water jacket ruptures due to corosion that water is able to enter the engine via the exhaust ports. Often times when you go to restart the engine it will be hydrolocked(cylinders full of water, motor won't crank over).

Did you see any steam in the exhaust recently?


Hope this helps!

Joe

I'm not a mechanic, but worked with a friend of mine who was, during winters when fiberglass/wood buisness got slow.

 

thanks for your insight. I was looking on this site last night after I posted the thread and discovered what I hope is the problem. We had a severe rainstorm here and my stern was flooded. If this is the source of the water I should be ok. I am flushing the engine out and am going to do several oil changes until the oil is clean coming out. Then I'll fire it up in the water and see how the oil is after running it in the lake. I will have dog ears on it when I work on it at home. Thanks again for your help and if anyone has any suggestions I am all ears. I might also be looking to increase performance on my engine, if there are any ideas I would more than greatful to hear them.

 

You are doing the right thing by changing the oil and filter. If it is a closed coling system, did you notice any loss of coolant.

In cold climates metal can sweat, engines too , on the inside as well as the outside. You could just have a sweaty rocker box internally and this was coming out from the filler cap. If the entire contents of the engines oil is milky then some thing is wrong. With a 79 you should have proper crank case recirculation that should not let this happen, however Proceed with caution.

 

thank you once again. My enginge's cooling system is raw water. I'm positive that the water came from the rain and entered around the dipstick. Been trying to work at it, but I am on nightshift and keeping my fingers crossed until tomorrow when I can finally work on it. It's been 3 days that the contaminated oil has been in the engine. I've also heard about using atf to flush out the water. This was such a shame, the engine had been running excellent all season, even better than last. I have a heavy boat, since it's a 79 crestliner crusader 175, and with five adults in the boat 2 weeks ago I planed no problem. I also have an oversized prop (13.75 dia with 21 pitch) that I'm going to change. Factory prop for this engine is 14.25 with 19 pitch if my memory serves me correct. I'm looking for ways to bring this old lady back to life, I know that it had more power before, any ideas on what I can do on a limited budget (second baby on the way)? I would greatly appreciate it. I also read on one thread about someone putting down the people and their knowledge on here, I just want to say I've been looking for a site like this for a long time.

 

I hope you are correct in your rain water theory. I dont think the 'milky oil will do much if any damage if you get it out now. A sump full of water that has not been emulsified into the oil would be a different matter, good luck.

 

thank you once again jackfrost, I'll be on tomorrow to post how it went. Any ideas about getting more power out of my baby? I have maxed out at around 35-40 mph

 

Sounds like your doing very well at those speeds. At a guess is it an alluminium fishing boat?

,---it s just that you said you were out fishing!!

 

jack frost, actually it's a fibreglass closed bow, deep V. The boat is heavy, with trailer is about 2900lbs. it's a real classy boat with a lot of teak trim. This fall into next spring, I will be gutting the floor and seats to rebuild them and switch from carpetting to a non-slip plastic covering, so I can wash the fish junk after a good day. My next boat will be an aluminum fishing boat, but this one is good to start out with, and the price was right when I bought it. I've driven boats since my early childhood but this is my first boat that I own.

 

jackfrost, I have drained the oil from my engine and man was it thick. I filled it with motor oil, turned the engine over without firing for about 20 seconds, everything sounded alright, I drained that oil and then filled it with another 5L. I wasn't able to fire up the engine as the boat dealerships around here were closed and all I had was an old oil filter from last fall when I changed the oil for winter. I pulled the spark plugs to make sure my rings were sealing and they were normal. I drained the water from my exhaust manifold to check for any oil and it was clear. I think I might be right about the rain theory for the engine turned over fine and there were no abnormal noises, rubbing or whining, the true test will be once I have completely flushed the oil and run the engine. I was wondering what kind of solvent you would suggest for cleaning my valves, I was thinking about taking the valve cover off and cleaning up my head thoroughly. What do you think?

 

I would'nt bother, just change the oil 2 times at least, running for an hour on the final time. Dont use ATF or flushing oil. After a week of trouble free running, I would consider one more time with a good quality filter. For flushing just use cheap engine oil and cheap filters. SAE 30 would be ok

 

thank you once again jackfrost. I'm on my second batch in the engine, and once I get some new oil filters that fit I'm going to run it for a bit, flush it again and then add the final mercury oil and filter. How would I go about switching the engine to synthetic, or is it worth it, there are no leaks and I've never had to add oil.(I check it every time I go on the water with the age of the engine) Would you know the proper size prop for my engine, I can't remember the ratio but my optimum rpms are between 4200-4600 and currently I am getting about 3600-3800 flat out and only me in the boat. Thanks once again, you wisdom is being absorbed.

 

Your wisdom is being absorbed?? good heavens your embarrasing me, I am just a mechanic, there are other forum memebrs who can help on specifics of your application.

Propellor sizes are an individual choice,-- weight of boat due to your fishing equipment, primarily, However the manual will say that max RPM should be achieved at full throttle. My own personal opion is that I would aim for slightly under RPM, 200/400 under

Synthetic oil is good but expensive and unecessary for a basic American V8 engine.

 

jackfrost, I have now gone through my 4th oil change and ran my engine for about 5 mins. there was a rumbling sound when I increased the rpm's and once I shut it down I pulled the spark plugs to check. The oil was still a shade cloudy, and the spark plugs had a bit of oil on them, especially #4. I plan on flushing it once more, then run it on a river by here for about an hour. But before then, I'm going to do a compression test on my cylinders to make sure my rings are still ok. Does it sound like I am doing the right thing? when I was idling the engine, it was running very smooth. Any suggestions from anyone would be greatly appreciated.