oil coming out exhaust !!!!!

[alameda]

hi

when I rev my engine (1cyl Yanmar in an Ericson 27) in reverse, to get some way on to back out of a slip, it spews out alot of oil, or if out in the open I put it into reverse and then rev it up high, alot of oil comes out.

is this because I need new piston rings?

or is there another reason?

thanks



john

[David M]

How many hours does the engine have? Is there a difference between when the engine is cold and when the engine has warmed up?

[AnchorageGuy]

john, are you sure it is oil or are you just seeing a slick? Anti-freeze will also create a slick. Try if you can to catch some exhaust discharge in a bucket and see what you have.

It is far more likely you are seeing diesel fuel rather than lub oil. Stick a bucket under the exhaust and get a sample, smell will tell you.

Some unburned fuel is normal for older design engines when the throttle linkage is rapidly opened, and lots of fuel is put in to bring the engine up to speed, sometime with accompanying black smoke, so you MIGHT not have a problem.

If this happens after the engine is at stable speed, then you have other problems. Maybe just overlaoding the engine with a bad prop selection, or, if this is a new situation, bad injector(s) should be considered, or poor compression might also be an issue.

[psteele235]

Make sure the prop and hull are clean. Just happened to me and a diver cured everything.

[never monday]

can't be anti freeze. None of the one cylinder Yanmars were FWC

[Pblais]

Are you able to see a drop in the oil level? An engine not fully warmed up might have uncombusted fuel. How does it behave after it's warmed up?

[Chief Engineer]

Seriously underpowered.....Overloaded engine....fuel sheen

[Ex-Calif]

Originally Posted by Chief Engineer

Seriously underpowered.....Overloaded engine....fuel sheen

I tend to agree. 1 cylinder? How many horses and how heavy is your boat.

Check the oil before each days sailling (you do that right?) and see if it consumes oil. If not the sheen has to be diesel - unburned diesel.

[alameda]

the engine in question here is the original engine from when the boat was built in 1978, so it is pretty old.

I will collect some of the discharge and see what I get.

It really seems to put out gunk when in reverse and I rev the engine to get some way on.

thanks for all your replies.

john

[Sea Stewards]

HI

I had a problem like this with a mismatched prop: new engine with high rpms, old prop with larger diameter and wrong pitch. Repitching it helped.