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John Deere D-120 Lawn Tractor leaking oil when I turn the mower on

Ray Seguin's Avatar

Join Date: Jul 2014
Posts: 4

07-12-14, 12:04 PM   #1  
John Deere D-120 Lawn Tractor leaking oil when I turn the mower on

This is my first time post. I have a little 2011 John Deere lawn tractor, with 77 hours on it. It has a 21hp Briggs one cylinder engine. Today while cutting the grass, I got a slight smell of smoke, and I then I could see a bit of it as well. Stopped immediately, and notice that a bit of oil that had dripped on the chassis. First thing I checked was the oil filter to make sure it was tight, and it was. Started the engine, and cleaned any remaining oil residue, to try and spot the leak...but I couldn't find anything, and the leak seemed to disappear. So close the hood down, and continue cutting the grass, but then I could see a bit of smoke again, I stop the engine, and take a look, and again, there was oil on the frame. So I cleaned up again, and started the engine again, still nothing would leak, so I turned the deck on...and VOILA....the oil would start leaking through the little round screen filter on the fuel pump. Why would engine oil come in through the fuel pump ? This tractor's warranty is over, but it only has 77 hours on it. I use it to cut grass only on my 1/2 acre flat smooth property. Could it be just a fuel pump problem, or am I looking at something more serious here like a head gasket or something ? The fuel pump appears to just 'snap" into some cheap plastic that covers the engine, but I didn't try to remove it for fear of breaking it ? Any suggestions from anyone who has experienced this would sure be helpful. Thanks for listening..

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31YTech's Avatar

Join Date: Feb 2008
Posts: 1,263

07-12-14, 04:23 PM   #2  
Hello Ray Seguin,

When a fuel pump diaphragm springs a leak the crankcase pressures (impulse) cause oil to exit the brass vent/filter. A new replacement fuel pump is all that's needed, Also check your oil level and smell it checking for signs of fuel contamination. They can also seep fuel into the engine crankcase, If not caught in time can cause internal engine failures.

Good Luck

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