Craftsman lawn mower is dumping its oil

[KennyV]

I don't see any washer, seal or gasket where the oil filler tube enters - but I might be missing something...



My fingers are crossed that it's NOT part 20, the rubber oil seal at the top of the shaft...

Tom

I don't think there is a seal at the fill tube... I believe that screws into the crankcase... It could be loose.

It would be more likely that# 75 leaks before #20... lower seal gets more abuse.. :smile:KennyV

 

[Motorman]

Oil leaks around the dipstick area are common. First clean the area around the dipstick tube and remove the tube. There will be either an o-ring at the bottom of the tube where it fits into the crankcase or a rubber grommet that the tube slides into.

 

[TBm]

Motorman: There will be either an o-ring at the bottom of the tube where it fits into the crankcase or a rubber grommet that the tube slides into.
KennyV: I don't think there is a seal at the fill tube... I believe that screws into the crankcase... It could be loose.

You guys are really making me curious. Gonna have to tear it apart and see who's right... :biggrin:


HERE'S THE PARTS DIAGRAM LINK AGAIN

It would be more likely that #75 leaks before #20... lower seal gets more abuse.. :smile:KennyV

I'm seeing no leaks under the engine, so no problems with #75 (lower seal). LOGIC: If lower seal is more likely to fail than upper seal, and lower seal is good, then upper seal should still be very good.

I think I had pulled the flywheel off last time I saw #20 upper seal. That was NO FUN because I don't own the correct puller I hope to avoid that this time...


OIL BREATHER System:
#6 Breather Element - is this thing soft like a filter, or is it hard plastic, or metal?
#10 Breather Valve Body
#12 Breather Tube

#6 and #10 appear in the diagram just above the engine block. The #12 Breather Tube is at lower left, attached to #240, the air cleaner body. My paper air filter got ruined by crankcase oil while the mower was upside down.

QUESTION: If the Breather Tube (#12) became clogged, or kinked or in any way obstructed during the gearbox repairs, would it cause the engine to blow its oil out? If so, from where is the oil exiting the engine? Maybe right where that oil fill tube enters the crankcase?

COULD IT BE AS SIMPLE AS THIS: THE AIR FILTER is TOO DIRTY (or clogged with oil)?

If the crankcase can't "breath" properly, maybe that would explain the extreme pressure (or so it appeared to me) when I removed the oil fill cap while the engine was running...?

 

[TBm]

Nobody...? :frown:

 

[KennyV]

If the crankcase can't "breath" properly, maybe that would explain the extreme pressure (or so it appeared to me) when I removed the oil fill cap while the engine was running...?

A small engine will have such a large pulse in the crank case that you can never remove the oil fill cap with the engine running...
It is vented into the intake manifold with a tube... But it is always going to blast out a lot of air if you open it with the thing running... KennyV

 

[TBm]

Thanks for the confirmation, Kenny.

The other points in my earlier post are:

Q1. Could a blocked paper air filter build up enough crankcase pressure to cause oil to exit the crankcase?

Q2. Could a blockage in the oil breather hose that runs to the air filter housing cause a build-up of pressure, enough for oil to exit the crankcase?

If either answer is YES, where is the oil blowing out from?
This whale's definitely got a "blow hole" somewhere... :biggrin:

 

[Motorman]

There is definately an o-ring style seal at the end of the dip stick tube. You may not have found it because it blew out or it was never installed.

 

[TBm]

There is definately an o-ring style seal at the end of the dip stick tube. You may not have found it because it blew out or it was never installed.

Motorman ==
Thanks. I don't see one on the exploded diagram from the manual, so I'll have to dig in and see for myself. Been dragging my feet because it's so blasted cold here. Not sure how I'll purchase a new one without a part number, though...

P.S. How's Maryland these days? I used to live in Prince George's County, in Greenbelt and also in Croom. Fond memories, mostly.

 

[adan]

Hi TBm! I'm trying to follow the discussion with the wide eyes of a college student trying to learn engineering. It's quite tough to follow without seeing an actual unit. I just wonder if you ever brought this thing to a technician nearby?

P.S. How's Nebraska today?

 

[TBm]

Hi TBm! I'm trying to follow the discussion with the wide eyes of a college student trying to learn engineering. It's quite tough to follow without seeing an actual unit. I just wonder if you ever brought this thing to a technician nearby?

P.S. How's Nebraska today?

This would be a tough way to learn Engineering, but on the other hand, I applaud your interest in gaining a PRACTICAL understanding of Engineering principals. I wonder how many graduate each year with heads full of theory, and nothing more...:wink:

Local Technicians are expensive. As long as it's something basic (outside the combustion chamber and carburator) I should be able to handle it.

As for Nebraska, it's frigid winter blasts from Canada and seething summer heat from Texas and Oklahoma, with nothing to slow it down but a few barbed wire fences along the way. :biggrin: I much prefer Maryland for climate and scenery, but not for politics or social norms. Turns out I'm midwestern at heart, just can't seem to get used to the scrubby little trees...:biggrin:.

Adan, are you a college student or are you somenone looking to retire soon? Maybe you were using the "college student" reference merely to describe the extent of your interest in the topic? Either way, the more the merrier.