Need help on john deere L120 lawn tractor

lenny180 · May 3, 2006

hi guys-i am having a problem. L120 is 3 years old and has 47 hrs on it. Starts up strong and runs that way for half hour then it just doesn't sound as strong and seems to bog down when cutting. i have given tune up and replaced fuel filter,fuel pump and i don't know what to do. i was gonna take it somewhere but didn't yet. any suggestions??? thanks

Charlie_in_TX · May 5, 2006

First welcome aboard.

You need 3 things for a good running engine, compression, fuel and properly timed spark. 2 things come to mind. Could be the spark coil overheating or loosing compression when warm.

Give this a try. When cold, take the spark plug out and see what kind of spark you get. Run a compression test. Use it until you notice this 'bog down' condition. Recheck the spark and see if it is the same quallity of spark and retest compression. That should give you a direction to pursue to correct your problem.

lenny180 · May 5, 2006

Thank you Charlie. I will do that this weekend. hopefully is nothing major

JeepOne · May 5, 2006

I've got the same mower and when I had 52 hours on it (now have 150) it would bog down just like your problem. Do this! Loosen the fuel cap while its running and see if its better. I'll bet it is!! My problem was that the fuel cap breather hole was plugged up. Just unplugged it with a piece of wire and all is well. Give it a shot. Sure won't take long to find out.

Let me know how this works for ya!!

lenny180 · May 6, 2006

Thanks,i'll try that also.hopefully that's it.It still is a baby /forums/images/graemlins/grin.gif

lenny180 · May 16, 2006

I finally found out its the iginition coil. the one plug has no spark. The other one is good. Is that a part i need to order or can i go in and pick one up??

lenny180 · May 16, 2006

I finally found out its the iginition coil. the one plug has no spark. The other one is good. Is that a part i need to order or can i go in and pick one up??

TERRYT · Nov 19, 2008

Just a thank you for the heads-up on the gas cap vent plug clogging. This saved me a lot of bucks. The L120 would run for about 15 min just fine and then the engine started cutting out . Let it sit for a couple hours and it would start again. The manual has you check for clogged fuel filter and a couple other items. Tried everything in the manual and the engine still cut out after about 15 min. I finally read this tread and went out to the mower to try the gas cap. Soon as I unscrewed the gas cap and heard the vac release I knew you were right. Works great now.

Thanks to all.

biggerjer · Nov 6, 2010

I know these are old posts but right on anyway. I had same problem with L120 only mine has adjustable vent on cap which had become screwed all the way in. opened it and problem was fixed. Thanks much for the great advice.

Jerry

rustykelly · Nov 19, 2010

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mlebied · Nov 4, 2012

unbelievable! I was mowing the lawn for the last time this season, and halfway through the job, the tractor quit. I could hear it starting to run rough, like it does when the fuel is empty. Looked down and confirmed the tank was almost full. Fiddled around with a few things before determining the engine wasn't getting fuel. The nice design of the JD fuel filters allow me to easier determine fuel flow. After awhile I resorted to the best troubleshooting tool - the internet - and found this post. Surely it couldn't be ~that~ simple. But sure enough, cleaned out the fuel cap vent with a toothpick - and WOW! I saw the fuel start flowing through the filter and it started right up. Still can't believe it was that simple - but glad it was! really did not want to have to take the tractor apart in the cold, windy weather today! Thanks for the tip JeepOne!