gas in the oil

[Anonymous Poster]

Anyone know why I would be getting gasoline in the oil on a John Deere LX188? Changed the oil this afternoon, and the oil was very thin, and smelled like gasoline. I have not noticed any problems with the way the machine runs, other than sometimes the exhaust smells like the carb may be too rich. Have only noticed this in the last week.

Thanks for any help.

 

[Bird]

rlk, I don't even know what a John Deere LX188 is, but I bought a new Toro walk behind lawnmower in 1969 with a Tecumseh engine and even though I only had a small yard, after two years, I could only mow the yard twice and then had to change oil because the crankcase would be full of gasoline. The dealer said it was blowing by the rings and the only solution was a new engine. I had a better solution; I bought another brand of lawnmower and haven't bought anything with the name of Toro or Tecumseh on it since.

Bird

 

[scruffy]

rlk, if that machine has an external fuel pump, put a new gasket on it! I've run into two vehicles through the years that leaked gas into the oil, and both were caused by a faulty 25cent gasket.
The first one was rather interesting, not to mention puzzling! The turkey would fire up, run for about a minute or so, and blow the distributor cap off, which was the reason it was brought into the shop. It had a hollow core distributor shaft, and the fumes would drift up the shaft until enough built up in the cap to ignite. Took me two days to figure it out, and 20 minutes to put a gasket in it.

 

[jimmoore]

The 12.5 briggs & stratton engine on one of my mowers was doing the same thing. Found that the needle valve was sticking and the carburator bowl was overfilling. Was ok while running, but dipstick would show way overfull the next morning. I cut the rubber gasline and installed a little plastic shut off valve and solved the problem w/o overhauling the carb JIM

 

[jimmoore]

The 12.5 briggs & stratton engine on one of my mowers was doing the same thing. Found that the needle valve was sticking and the carburator bowl was overfilling. Was ok while running, but dipstick would show way overfull the next morning. I cut the rubber gasline and installed a little plastic shut off valve and solved the problem w/o overhauling the carb. I just close the valve when finished mowing. JIM

 

[gordon]

Not being sure of what engine is on that your tractor or what style of carb you have I can only make a stab in the dark. But here is my stab, I believe that Jim might be right all it takes is a small piece of trash or even just gas varnish over time can cause the bowl to flood. Does it start up allright? Does it have a manual or automatic choke? Any visible black smoke while running or under heavy load? Have you ever had a fouled plug on the tractor?

I would also pull a plug and inspect it as well just to see if thats the problem. A fouled plug can put gas into the pan real quick. Or ring blow by as Bird already said is another possibility. But a fouled plug or spark problem can have the same symptom. If it comes to that a leakdown test would answer that question. But I believe its just a piece of trash in the bowl or you carb settings are alittle out of wack. One last thing check your air filter to be sure that its clean and not plugged up. That could also cause an over rich run condition.

Are you totally confused now?/w3tcompact/icons/smile.gif
I'm done rambling for now.
Gordon

 

[TomG]

My 12.5 BS ran out of gas while mowing. I filled the tank several days later. Just as I was starting to leave for town, I noticed gas puddling under the mower. Yep, the mover was proceeding to empty an entire tank onto the floor. I drained the rest into an old fuel can, and left.

I figured that it was a stuck float or leaking seat valve, and I would have to tear down the carb. I started taking the carb the next day, but then I though 'just wait a moment.' I retightened things and put a little gas in the tank. Worked fine--no problem. I checked the oil, which was at the right level. I did see the gas draining out of the carb throat, and I have no idea why it went on the ground instead of into the engine.

However, I guess I'll follow your example. I really don't know why any engine with a gravity feed fuel system wouldn't have a fuel shut-off. Seems like it should be a safety thing.

 

[Anonymous Poster]

Bird, Scruffy, Jim, Gordon and Tom:

Thanks for your input.

In answer to Gordon's questions: The engine is hard to start when cold. Once it warms up, it starts quickly and easily. It has a manual choke. The only visible black smoke is when it starts cold.

Monday I'll start with the simple things such as checking for a fouled plug; checking the air filter to ensure it is not clogged; then adjusting the carbureator. If all this fails, I'll look at the fuel pump; then possibly re-building the carb. Hopefully, one of these will take care of the problem.

I do have a shut off valve on the gas line, but have never closed it. Guess that is something I should do in the future.

Again, thanks for your input. You have given me several things to investigate.

 

[rlk]

Well, it turns out that gas was getting into the oil because of a blown head gasket. The tractor is at the dealer now getting a new one installed. Estimated repair is in the $400 range.

I was hoping for a less expensive repair. Seems like the major repairs always come when you least expect them.

Again, thanks for all who replied and offered suggestions.

 

[Bird]

Wow, that's tough! But at least we're glad the problem's been found and is being corrected.

Bird