Lawn mower question

[NAKID]

What would cause oil to come out of the muffler?

I last used the mower a couple weeks ago and all was fine. Today I go to start it as always and it doesn't start right away like normal. I pull it a couple more times and I see oil dripping out of the muffler. It finally starts and then dies. Starts again and sputters a bit as the oil burns off. After a couple mins it runs just fine, like nothing ever happened.

The mower is a Briggs and Stratton 5hp 4 cycle gasoline engine from Yard Machines...

[Jobu]

1.  Are you positive it was oil?  Not just carbon-fouled water.

2.  Are your valves in spec? 

Seriously, oil out the exhaust is never a good thing.  Think about how the oil would get there.  First it has to get around the piston - bad piston ring.  And then out the exhaust valve.

But being that's it a lawnmower, I wouldn't worry too much about as long as it seems to be working alright.

Oh, and I didn't that one could actually get grass to grow in Arizona.

[NAKID]

Yeah, it was definitely oil. I saw and thought it may be dirty water, but it was oil. The smoke screen when it started confirmed that.

I know how it could get there, but was asking why.

And yeah, we get grass to grow. I was mowing my back yard but just put down 1500 sqft of BOBSod in the front yard...

[IZ]

WTF Chris?! 

How could oil come out of an electric lawn mower?!

Oh..you don't have a plug-in electric lawn mower like the rest of the state!! 

[NAKID]

Screw that. Those things are pieces of junk!

[IZ]

Screw that. Those things are pieces of junk!

no sh*t!!  I had to get one though for my lil' patch of grass in AZ.    I gave it to my sis before leaving.   

[Ddan]

It's a Briggs.  Run it.   

[BWClark]

You're not storing it on its side are you? My grandfather was adamant that I didn't store his or my lawnmower on its side, saying that he reckoned oil would seep into places it didn't belong....   

[ducpainter]

I have an old Briggs that if tipped too far towards the muffler side will do the same thing.

It's only about 30 years old, so I don't think it's worn out. 

[ODrides]

Pouring oil into the air filter because you can't find the oil fill tube could do it.  So I've heard.

[Howie]

Unless it was recently tipped on it's side a compression test is in order.

[junior varsity]

Just stick a bunch of photovoltaic panels on the top of it, and call it a day. I hear you guys have lots of potent sun.

[NAKID]

Not stored on it's side, but when fished mowing, I tip it forward against a wall to hose off the underside of it. I think the last time I did that, it spent more time than normal in that position. That was the night my dog got out and I had to chase him through the neighborhood for a couple hours...

[Randimus Maximus]

maybe you need to run higher octane fuel in it?  what's the owners manual recommend?  I only run premium in my power equipment.

[JohnnyDucati]

Not stored on it's side, but when fished mowing, I tip it forward against a wall to hose off the underside of it. I think the last time I did that, it spent more time than normal in that position. That was the night my dog got out and I had to chase him through the neighborhood for a couple hours...

Yup.  It's the tipping.  Mine did that (leaked oil through the muffler) when I would tip it up to hose off the crud underneath.  I gave that up after about the 3rd time I mowed the lawn.  Now, I just live with the crusty stuff underneath.  And no more oil through the muffler . . .