Oil In Gas

[Labrauer]

I have a John Deere L-111 riding lawnmower that is getting gas in the oil. I check the oil before I start to mow and after I check it again. After mowing the oil is way past the full mark and smells like gas. I drain it out and fill with oil again and after mowing again it is full again with oil and gas. Anybody know what I might try to stop this before I end up blowing the engine up. Oh by the way I have changed the fuel pump with know luck.

Thanks in advance,
Larry

 

[shiftsuper175607]

I have a John Deere L-111 riding lawnmower that is getting gas in the oil. I check the oil before I start to mow and after I check it again. After mowing the oil is way past the full mark and smells like gas. I drain it out and fill with oil again and after mowing again it is full again with oil and gas. Anybody know what I might try to stop this before I end up blowing the engine up. Oh by the way I have changed the fuel pump with know luck.

Thanks in advance,
Larry

The needle valve operated by the float is stuck open...but this leaks into the engine when the mower is not running...how it is getting in the engine while running is someone else's question to answer.

 

[jekjr]

The needle valve operated by the float is stuck open...but this leaks into the engine when the mower is not running...how it is getting in the engine while running is someone else's question to answer.

Most likely it is going in past the rings in the cylinder wall when the motor is not running. I had a carb problem on one of my mowers a while back and when we started it up immediately it blew a fog of gas out of the exhaust. Before it started the cylinders were so full of last that the starter almost would not turn it over.....

 

[bertsmobile1]

If you are getting oil in the crank while the engine is sitting then the responses from the previous posts would be correct.

However as you specifically stated you checked the oil level before you started to mow and after you finished when you found it had gone up
a reasonable assumption would be that the fuel had gotten into the crankcase while the engine was running.
If it was arriving there via a stuck float needle then you would be running very rich & blowing lots of black smoke.
You did not mention this so the assumption based upon the facts presented would be the fuel was entering the crank while the engine was running but not via the carburettor.

The only other place where the crankcase & the fuel system come into close contact is the fuel pump.
If it has a mechanical fuel pump then look at the seal and diaphragm
If it has an impulse pump then replace it as the diaphragm will have a hole in it and will be pumping fuel into the crankcase every time the piston goes up.

You can confirm this by checking the impulse line for fuel and double the confirmation by sucking on the impulse port on the pump.
It should suck in a little as the diaphragm moves in then hold vacuum for better than 2 minutes.

 

[Labrauer]

I have already replaced the fuel pump and it did not help that's not to say the new one wasn't bad. I forgot to mention in the thread before that now the engine will just idle and not rev up. I have checked the throttle cable to see if it was connected and it is. When started it doesn't have any smoke coming out of the exhaust. I have had this problem for some time and I had a guy work on the mower which it was fine for a couple of mowing but it is at the same old crap again. I had a carburetor kit put in the carb about six months ago so I am at my wits end here. Compression on cylinders are good from what I know so I don't see how gas could be by passing the rings. How do you set the float to see if it is set correctly? I haven't checked that yet. Every thread I have read on this subject is saying that maybe the float is set to high or the needle valve is leaking by. Other than buying a new mower or getting a new carburetor anyone know what else I can check. Oh by the way I was told by a lawn mower shop that I need to buy a carb or kit from the dealer as the ones sold off the internet probably will not be the right one so is this true or not.

Thanks in advance,
Larry

 

[bertsmobile1]

Firstly it would be a real big help if you posted the engine number ( Model & code ) .
I will assume that it has the 4000 seriec Briggs & Stratton which has an impulse pump.

That being the case did you fit it correctly?
The impulse line goes to the inlet in the middle on top
The fuel input & output are the ones ones the side.
Sounds like you have installed it incorrectly.

Now we need to get the facts strait and in chronological order.
It was serviced and had a carb overhaul after which the engine ran fine with the exception of the fuel leak.
The engine was pumping fuel into the crankcase but apart from that was running fine.
You replaced the fuel pump and now it won't throttle up.
Is that the correct time line. ?


Check the impulse line as requested and check the fuel pump as requested let me know what you find.
If the fuel pump you fitted was an unbranded one from China via an internet only seller then good chance it is trash.
Down here I have found several customers who fitted a $ 10 fuel pump bought off the net that had a neoprene diaphragm fitted so it went to jelly after a few months and in one case wrecked the carb and nearly the engine to boot from running lean which is why this one came into the shop as it was that hot it started to smell funny.

As for the other bit.
A lot of shonks make a lot of money by exploiting the greed / selfishness of the population by importing garbage from China for next to nothing then selling it on evilbay / Craigs / amazon etc for about 10 times what they paid for it .
Most of it comes from factories who "make a million for me that look exactly the same as this" and are unfit for the purpose if they fit at all.
Note not everything that comes from China is garbage , some of it is good and some of it is actually OEM parts, but sorting out the good from the garbage is not easy.

 

[shiftsuper175607]

If you are getting oil in the crank while the engine is sitting then the responses from the previous posts would be correct.

However as you specifically stated you checked the oil level before you started to mow and after you finished when you found it had gone up
a reasonable assumption would be that the fuel had gotten into the crankcase while the engine was running.
If it was arriving there via a stuck float needle then you would be running very rich & blowing lots of black smoke.
You did not mention this so the assumption based upon the facts presented would be the fuel was entering the crank while the engine was running but not via the carburettor.

The only other place where the crankcase & the fuel system come into close contact is the fuel pump.
If it has a mechanical fuel pump then look at the seal and diaphragm
If it has an impulse pump then replace it as the diaphragm will have a hole in it and will be pumping fuel into the crankcase every time the piston goes up.

You can confirm this by checking the impulse line for fuel and double the confirmation by sucking on the impulse port on the pump.
It should suck in a little as the diaphragm moves in then hold vacuum for better than 2 minutes.

Bertsmobile,
That is a great theory with the fuel pump bad diaphragm...
If it is hooked up wrong, no gas to carb, right?

 

[bertsmobile1]

The pump is a simple diaphragm that gets sucked in & out by the crankcase pressure pulses.
I don't think there is even a spring in there but it has been a while since I had one apart but the two fuel lines are on one side of the pump and the impulse is on the other side .
So if connected wrong, no fuel flow till the diaphragm splits.
The metal ones
They used to be marked with in & out arrows on the fuel lines and nothing on the impulse line.
It has been so long since I replaced one I really can not remember but good you should have a problem with it as when I went to check, I have run out so time to reorder a 1/2 dozen.
They retail around $ 45 down here and you can buyones that look the same off Ali Barba for 99¢ in lots of 200 or more but they are junk.
Some moron was flogging them off on evilbay for $ 10 and lot of cheapskates got done like a dinner.
I had 2 customers get caught and took delight in showing them where they came from & how much they got ripped off.
A little latter the evilbay seller vanished

 

[bertsmobile1]

The pump is a simple diaphragm that gets sucked in & out by the crankcase pressure pulses.
I don't think there is even a spring in there but it has been a while since I had one apart but the two fuel lines are on one side of the pump and the impulse is on the other side .
So if connected wrong, no fuel flow till the diaphragm splits.
The metal ones used to be marked with in & out arrows on the fuel lines and nothing on the impulse line.
It has been so long since I replaced one I really can not remember but good you should have a problem with it as when I went to check, I have run out so time to reorder a 1/2 dozen.


They retail around $ 45 down here and you can buy ones that look the same off Ali Barba for 99¢ in lots of 200 or more but they are junk.
Some morons were flogging them off on evilbay for $ 10 to $ 20 and lot of cheapskates got done like a dinner.
I had 2 customers get caught and took delight in showing them where they came from & how much they got ripped off.
A little latter the evilbay seller vanished