2021 John Deere has a Non vented, recirculating fuel system that may have a clogged return hose. Can it be bypassed or unclogged easily?

[rayikeo2]

My S240 Lawn Tractor mower gas system was keeping the mower from running longer than 5 minutes. I found the fuel hose from the filter to the fuel pump was clogged. I replaced that section, and now it is running but the return line from the carb to the fuel tank is also clogged. I can't blow through the line, but the mower is running now. Can the return line be bypassed, or will I have to run a new line from the carb to the gas tank? The fuel cap is unvented.
Maybe the return line is ok, there is a pressure vent somewhere in the system and it may be in the cap, I don't know exactly how this system works.

 

[sea2summit]

A gas mower with a carburetor has a return line? I've not heard of such a monster but fuel line is cheap, I'd just get a new piece and replace it.

 

[beenthere]

carb system system with return line ..

If plugged lines, I'd consider replacing lines and also pin-pointing source of dirt causing the plugging

 

[rayikeo2]

A gas mower with a carburetor has a return line? I've not heard of such a monster but fuel line is cheap, I'd just get a new piece and replace it.

The problem with this return line it goes under the body and into the tank at a hard to reach place without taking things apart, which I would rather not do. The new mowers now have this recirculating fuel system for emission control. It keeps fuel vaper from escaping into the air. Fuel caps have no vent hole. Not all the lower priced mowers have changed to this type of closed vent system.

 

[beenthere]

"..rather not do.."
What is the alternative?

 

[sea2summit]

The problem with this return line it goes under the body and into the tank at a hard to reach place without taking things apart, which I would rather not do. The new mowers now have this recirculating fuel system for emission control. It keeps fuel vaper from escaping into the air. Fuel caps have no vent hole. Not all the lower priced mowers have changed to this type of closed vent system.

Get a chunk of 1/4” all thread, about an inch and half should do. Stick half it in your new hose and put a hose clamp on it, put the other half in one end of the old hose and clamp it. Pull on the other end of the old hose.

 

[rayikeo2]

carb system system with return line ..

If plugged lines, I'd consider replacing lines and also pin-pointing source of dirt causing the plugging

My dealer said it was probably a bad fuel problem from using 10% ethanol fuel that may be old or contained contaminates.

 

[rayikeo2]

"..rather not do.."
What is the alternative?

I was hoping that it could be blown free or reamed with something that wouldn't damage it. Another thought, I need to learn more information about how this new system works.

 

[rayikeo2]

Get a chunk of 1/4” all thread, about an inch and half should do. Stick half it in your new hose and put a hose clamp on it, put the other half in one end of the old hose and clamp it. Pull on the other end of the old hose.

That sounds like a good idea, I may try that, after I get some new fuel line. Thanks.

 

[RandyT]

A gas mower with a carburetor has a return line? I've not heard of such a monster but fuel line is cheap, I'd just get a new piece and replace it.

All mowers after 2012 cannot bent directly to the atmosphere due to EPA regs. The line he is talking about is a vapor line and could either connect to the roll over valve in the top of the tank or connect to a charcoal canister similar to the coffee can on cars of the 70's. I have had a few come through the shop over the years due to clogging issues with the roll over valve due to people trying to squeeze the last drop of fuel into the tank resulting in bricking the valve.

Cannot be legally bypassed, but it also appears that JD doesn't offer a replacement of the valve itself which would require replacement of the fuel tank. This system operates very similar to the automotive evap systems but there is no purge valve. So when running the tank is actually under a small amount of vacuum but the fuel pump will overcome that vacuum and still operate, I have had a few mowers in the shop over the years that had the gravity flow tanks which I used to use the 40 micron filters on but starting having issues with fuel flow because of the vacuum with low tank volumes and had to switch to the 75 micron filters.