L120 Fuel Problem and Technical Manual

[Glessed]

Mower doesn't continue to run after starting. Lasts for about 20 seconds. Appears that gas flow is restricted. I replaced the two gas lines from the fuel filter to the carburetor and gas appears to be pumping OK when the line is disconnected. The fuel shutoff solenoid clicks when the key is turned on. Also replaced the battery.

The fuel filter does not fill. It appears that there is some kind of restriction somewhere in the fuel flow path. I'm totally confused. Can anyone suggest what to do next?

Also, I just bought a Technical Manual (TM2026) and it is only one step better than the Operators Manual. It cover electrical decently but does a poor job of showing the different subsystems and their components. Can anyone recommend a better Technical Manual or Service Manual that I can buy to aid me in current and future troubleshooting?

 

[jinman]

What you are describing is exactly how my LA145 acted when it had a stuck float needle valve. As soon as all the fuel was used up in the float chamber, the engine would die (about 20 seconds after starting). I could remove the hose on the carb side of the fuel pump and blow into it with 30 psi air. That was enough to unseat the float valve and the mower would run fine after that. I did that routine for several months until I got shamed into fixing it correctly. Finally, I replaced the float needle and it has worked fine since. I think ethanol in gasoline makes the rubber needle valve soft and sticky after awhile.

BTW: It is common to not have the filter completely fill with fuel. Mine is always 2/3 to 3/4 full and it doesn't seem to be a problem.

I also believe your engine is a Kohler, but the carbs on Kohlers and Briggs engines are very similar.

 

[Glessed]

Thanks, I'll investigate the float needle possibility. I have the Briggs engine.

 

[BATTY54]

Check your fuel cap vent the L series were known for plugging up the vent hole in the cap. I fixed three as well as my own one year.

 

[Glessed]

I'm beginning to really like this forum. I will try the ideas tomorrow. I'll let you folks know what happened.

 

[gtunney]

I had a similar problem three years ago on my L118 and it was the vent hole in the gas cap. I check it every time out now.

Check your fuel cap vent the L series were known for plugging up the vent hole in the cap. I fixed three as well as my
own one year.

 

[Glessed]

Thanks for your input.

 

[Glessed]

I fixed the problem.

The nut inside the fuel float assembly that holds the fuel shutoff soleniod (bolt) in place has a small jet in the side of the nut as well as a jet in the middle of the nut. The side jet was an area that could not be reached with the carburator spray tube (spray can). I removed the fuel soleniod and cleaned both of the jets, then reassembled. Worked perfectly. It's amazing how a little dirt or varnish can impact things.

I also noticed that the air vent on the gas tank cap was starting to get clogged. Also noticed that the air intake on the fuel pump was dirty. Cleaned both of these items as well.

Next time (if the symptoms happen again) I will be able to do the job within 30 minutes. I can only imagine what it would cost if the repair shop performed the same task.

Thanks for your ideas and inputs.

 

[stuart]

Any chance you might have a photo or two that indicates where I might locate: "The nut inside the fuel float assembly that holds the fuel shutoff soleniod (bolt) in place has a small jet in the side of the nut as well as a jet in the middle of the nut. The side jet was an area that could not be reached with the carburator spray tube (spray can). I removed the fuel soleniod and cleaned both of the jets, then reassembled."
Thank you very much a picture would help me greatly.

 

[Glessed]

See attached. The fuel shutoff solenoid is located at the front/middle of the mower. There are two wires going to it. The carburator assembly needs to be removed (4 bolts). The bowl can then be removed by taking out two screws. Then you will see the nut I was talking about at the bottom of the bowl that holds the fuel shutoff solenoid. Good luck.