L120 can't get fuel
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If removing the cap doesn't help, then you don't have a clogged cap. The flow in an L120 is: Tank>Filter>Pump>Carb. The pump can only work so hard against a clogged filter or fuel line.
Try this: Pull the inlet hose off of the filter. If the tank is full, gas should flow out. If not, blow back through the hose. You may get crap showing up in the tank, but the line should now flow free. Try that and let us know where you're at.
If fuel flows freely when you first remove the line, then the filter is clogged.
As an aside, how do you know fuel isn't getting to the filter? Under normal conditions, the fuel visible in the filter may only be about 10% of the filter volume, depending on tank level.
Also, when you changed the fuel pump, did you change the vacuum pipe running to the rocker cover? If the rubber is split or cracked, the pump won't work properly (or at all).
Paul
Try this: Pull the inlet hose off of the filter. If the tank is full, gas should flow out. If not, blow back through the hose. You may get crap showing up in the tank, but the line should now flow free. Try that and let us know where you're at.
If fuel flows freely when you first remove the line, then the filter is clogged.
As an aside, how do you know fuel isn't getting to the filter? Under normal conditions, the fuel visible in the filter may only be about 10% of the filter volume, depending on tank level.
Also, when you changed the fuel pump, did you change the vacuum pipe running to the rocker cover? If the rubber is split or cracked, the pump won't work properly (or at all).
Paul
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Okay, you heard bubbles. That's good. Now you need to get the flow going. The L120 is not a gravity fed system. There is a feed tube in the tank about 1/4" above bottom that exits at the top with a 90° fitting . The fuel line is connected to it. This is now all filled with air. Suck on the end like you were trying to siphon gas. I use a vacuum squeeze-bulb but you can use any way you feel comfortable with, until you get a solid flow of fuel. Put a fuel line clamp on the hose and reconnect to the filter. Remove the clamp. You're ready to move forward.
If it were my L120, I'd have two options: choke on FULL, crank until it starts. Crank time is limited to 12-15 seconds with a 1 minute cooling period in between. May take up to a minute of cranking, maybe two before it fires.
Second option: (what I'd probably do!) Remove the air filter cover exposing the air horn inlet. Place 10 to 20 drops of fuel directly in the air horn. Crank and it should fire and run for a few seconds. Repeat until it runs solid. What you're doing is using the engine to run the fuel pump at operational speed to prime the system until you get fuel to the carb.
Now, I'm making a few assumptions here. You initially said you weren't getting fuel to the filter. I assume you have spark (no grounded mag wires, fuel solenoid clicking, and the air filter isn't blocked) and the fuel tank is full or nearly so. I assume it was running when you put it away last Fall.
What the second option does is eliminate your complete fuel delivery system in your troubleshooting. If it fires when you directly place fuel in the air horn, then the air and spark parts of the triad are working. That just leaves solenoid, pump, filter or defective tubing. Filter would be my next choice. They can look just fine, but have a "slime" buildup on the filter element that blocks all flow. Replace on a regular basis, not on looks. Do NOT expect to see it full of fuel. Some fuel with the rest fuel vapor is good enough.
You can check the pump next. Remove the outlet hose going to the carb and feplace with a length of tubing that you can place in a can. Crank and make sure your getting pulsed flow into the can. You may need to use a battery eliminator or jumper battery if you drain the internal battery too far. After a short period (fifteen seconds MAX) fuel should be flowing from a good pump.
If you're good up to here, the only two things left are defective solenoid or stuck float. You can do a quick check of the solenoid by listening for a click when you turn the key from OFF to ON. It's energized in any position except OFF. The click is the shutoff pin being pulled by the electromagnet allowing fuel to flow. If it clicks, it's probably good.
There is a small chance that you have an air leak (split, hole, loose clamp) in the fuel line near the tank outlet. Since you have to pull fuel from the tank with a slight vacuum, any air leak here will give you trouble.
That's about all I have.
Good luck,
Paul
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Ok Guys, got the L120 to start and run. Blew out the fuel line again and this time fuel came out. Needed a little starter fluid and a new battery. New problem. After it has been running for about half an hour, it starts sputtering and won't run under load. Any ideas?
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I'd go back to the fuel cap again. See if it works any better (longer) with the gas cap loose. If the vent hole in the cap is clogged, then air can't get in the tank as gas is used up and eventually gas won't flow out of the tank naturally any more.
If that's not it, then I'd agree with the above... it's possible something is floating around inside the tank that's getting sucked back into the line again.
If that's not it, then I'd agree with the above... it's possible something is floating around inside the tank that's getting sucked back into the line again.
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Oft times, there's a small screen at the exit point of the tank. Fuel sloshing around may dislodge crud that it catches temporarily, but it's coming back to plug her up again. If there be one there, rip it out. Your inline filter is finer than the screen anyway. I know it hurts to put gasoline in the tank just to slosh it around and dump it out, and it must be done a few times, but you can dump it in a very clean pickle bucket or such and reuse after running it through cheesecloth so little is wasted. Pulling the rear fender is not a big, big deal..........done it many, many times. Good time to clean off the top of the hydrostat so that it'll run cooler.
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1,198 Posts
You describe the classic L120 symptoms of a clogged vent hole in the fuel cap. Follow greenmachine's advice and loosen the cap when it acts up and see if the symptoms go away. If it does, then the cap is clogged. I used to have a post on here which showed how to do it, but the pictures seem to have disappeared. You'll figure it out.
Paul
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just how hard is losin the fuel cap.. ya gotta take it off to fill it up..
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Ah, I see my error here. The post I was referring to was on "How to disassemble and clean an L120 fuel cap", not "How to remove a gas cap". :tango_face_smile:
Clogging happens every so often on my L120 given the heavy combination of dust, pine pollen and gas fumes.
Paul
P.S. Here's the link, but the pictures are missing, Not very helpful...
https://www.mytractorforum.com/12-john-deere-forum/157275-clogged-cap-syndrome.html
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