Oil problems

[warren casey]

A month ago on a three day trip I noticed that oil was splattering out the back of the engine, after a half + hour. I couldn't tell where it was coming from. I had just had the oil change a few week before and this was the longest I had run the engine. The boat is a 1971 Ericson with the original Atomic 4.

My question is: Was this blow-by because the too much oil was put back (I had local fuel dock change the oil for me. they weren't sure how much to put back). Or is there some kind of seal that had blown. Or????

I just took the boat out for another sail and ran the engine - it is still coming out but not as much? I checked the oil and it is just now down to the "needing some oil line" on the dip stick. I'm not sure what to do?

[Don Moyer]

In late model engines, the proper amount of oil to add is whatever it takes to bring the level to the full mark. In early model engines, the uppermost mark on the round dip stick equates to the full mark on late model dip sticks. The Atomic 4 is not very sensitive to moderate amounts of over-filling. If the crankcase is over-filled by several quarts over the full mark, there is a potential for some oil to work its way past the slinger seal behind the flywheel.

To be sure about where an oil leak is originating, it's almost always necessary to clean away the oil and to then "catch the leak in the act".

Here are some suggested places to look:

Most oil leaks occur along the carburetor side of the engine. Starting at the flywheel end of the engine and working rearward, leaks could be from the oil sending unit directly behind the flywheel housing (or from its connecting fittings), from under the valve cover, from between the block and fuel pump, or from around the oil pressure regulating valve.

If the leak seems to be from the rear of the engine, the rear seal around the output coupling could be leaking. However, almost all leaks from along the carburetor side of the engine usually run back along the upper ledge of the oil pan and end up dripping off the aft end of the engine. Therefore, to be certain that the rear oil seal is really leaking, it is necessary to thoroughly clean the aft end of the oil pan so that the oil can actually be seen to run down from the seal.

On the starter side of the engine, leaks are usually limited to the area of the water pump and accessory drive, with the shaft seal of the pump (the seal toward the engine) being the most likely. If this seal is leaking, you should be able to feel oil dripping out of the weep hole in the housing of the pump, between the mounting flange and the impeller section. Leaks from the oil seal of the water pump have the potential to leak up to a quart per hour in worst cases.

Still in the area of the water pump, the lower bolt of the mounting flange of the pump, or the lower bolt in the flange of the accessory drive (both of which enter into the crankcase) will at times allow a small amount of oil to drip from out of the crankcase.

If the leak is clearly coming from the front of the engine, it could be that the return holes in the flywheel housing below the air seal (or "slinger seal") around the front of the crankshaft are clogged. When these holes are clogged, oil being flung outward by the tapered collar around the front of the crankshaft cannot drain back into the crankcase, and it is leaking (instead) down behind the flywheel, along the front face of the flywheel housing, and out through a drain hole in the bottom of the same housing.

Don

[Jeremy Thompson]

Don,
If the leak is from a blockage in the return holes in the flywheel housing, how can be fixed?

Jeremy

[warren casey]

Thanks Don for the quick response. I will clean the back of the engine and try and find out what is going on.

I ran the engine when I returned a few days ago and it was still spitting oil - but not as much. Could just be left over leakage?? This is when I check the dip stick and it was down to "fill the oil line". How much oil does the engine take in a oil change?

I'm going out next week for two days and will keep a keen eye on the oil leak.

Warren

[Don Moyer]

Jeremy,

With the flywheel removed, you'll be able to see the collar with a sharp edge around its circumference (just outboard from the flywheel studs) and located in the center of the flywheel housing. You can then usually find the 6 or 7 small holes in groove along the bottom of the opening in the flywheel housing using a small length of safety wire.

Don

[warren casey]

I found the problem - it was one of the transmission cover plate bolts - it was missing!! No more oil leak! Just bought a new carb from Moyer Marine and will install it tomorrow.

Thanks again for all the help, Warren :D