Cub Cadet 3206 fuel starvation

[GTSRider]

...at my witts end on this one.....
was starving for fuel so ...
1. removed fuel cell and flushed with soap and water...all new grommets and pick up tube
2. new fuel line
3. new factory carb
4. new factory fuel pump
5. new fuel filter
can not seem to pump fuel up to carb...what gives ?
must new fuel line be filled with gas from carb down to tank to prime system ?
Thanks ,
Pete ,
Hudson Valley, NY

 

[Bob_Bainbridge]

Try loosening the gas cap in case the vent is plugged. This usually would cause fuel starvation after running awhile so isn't likely. Changing so many components always leaves the possibility of one being defective. Make sure all hose clamps are air-tight on suction side of the pump. Check for stuck float in new carb.

Bob B.

 

[TnAndy]

Follow the gas.

Pull the line off the tank....does gas run out ? No ?...obstruction in tank. Yes ?....put the line back on, take it off at the next connection point, repeat. Keep going until you find the problem point.

 

[GTSRider]

Andy...this fuel delivery has to be the dumbest design in garden tractor history.....the fuel pick up tube is at the top of the tank, and sits about 1/2 inch from the bottom, so as not to pick up any debris..... so gas must be pulled straight UP the pick up tube, then fuel line goes down, and follows frame rail , then must go straight up again, to the fuel filter and then to the carb. I don't think the diaphragm fuel pump has the suction to pull up fuel into an empty fuel line. I'm going to try to fill fuel line with gas to help overcome the air in fuel line. Like I said fuel tank is squeaky clean with all new pick up tube and grommets.

 

[TnAndy]

You might try pressurizing the tank with 10-15psi of air. Take a pc of flat plastic or thin plywood to hold over the tank filler opening with a 1/4" or so hole drilled in the center. Stick an air blower nozzle in the hole, with the air pressure cranked way down (don't want to blow things apart), hold the plastic/wood down tight and put some air pressure in.....that should force gas out the pickup tube toward the pump....leave the line off to the pump so you can see it squirt out. Then reconnect the line and try to see if that primes the line enough to work.

If not....my suggestion is buy an aftermarket, small volume, electric fuel pump. I had to do that on my Miller Bobcat welder. Not because it wouldn't pick up fuel from the base mounted tank, but because the stupid diaphram would blow out regularly and engine oil spew out. I simply replaced it with an electric pump. End of problem.

Edit: Something else you might try is a squeeze bulb hand pump....often used on outboard boat tanks. You can squeeze the bulb and force fuel on toward the pump. My sawmill engine is a Briggs 18hp, and uses a boat tank with one of those bulb pumps in addition to the diaphram pump on the engine. If I run out of gas, I pump it a few times to prime the line to the engine pump.

 

[Richard001]

You might try pressurizing the tank with 10-15psi of air. Take a pc of flat plastic or thin plywood to hold over the tank filler opening with a 1/4" or so hole drilled in the center. Stick an air blower nozzle in the hole, with the air pressure cranked way down (don't want to blow things apart), hold the plastic/wood down tight and put some air pressure in.....that should force gas out the pickup tube toward the pump....leave the line off to the pump so you can see it squirt out. Then reconnect the line and try to see if that primes the line enough to work.

If not....my suggestion is buy an aftermarket, small volume, electric fuel pump. I had to do that on my Miller Bobcat welder. Not because it wouldn't pick up fuel from the base mounted tank, but because the stupid diaphram would blow out regularly and engine oil spew out. I simply replaced it with an electric pump. End of problem.

If you use an electric fuel pump, you will be hard pressed to find one that has low enough pressure rating to work with your carb. However you can buy a regulator to limit the pressure at the carb.

Have you checked the pulse line that goes to the pump? Could be plugged, disconnected or broken.

Edit: Something else you might try is a squeeze bulb hand pump....often used on outboard boat tanks. You can squeeze the bulb and force fuel on toward the pump. My sawmill engine is a Briggs 18hp, and uses a boat tank with one of those bulb pumps in addition to the diaphram pump on the engine. If I run out of gas, I pump it a few times to prime the line to the engine pump.

Richard

 

[TnAndy]

Got mine at local NAPA store, but here are a couple of online sources:

Facet FEP04SV Posi-Flo Electric Fuel Pump 1.5-4 Psi, Includes Clamps/Fittings $48.05

Amazon.com: Facet FEP4SV Posi-Flo Electric Fuel Pump 1.5-4 Psi, Includes Clamps/Fittings: Automotive

Facet Fuel Pump, 15 Gallon/Hr @ 1psi

Facet Fuel Pump, 15 Gallon/Hr @ 1psi, 1/8 NPT - Pegasus Auto Racing Supplies

 

[JRobyn]

You can pretty easily function-test that little impulse fuel pump. Completely remove it and clean it good. Flush a little warm soapy water through it from every direction. You should find that you CAN'T from the carburetor end, because the pump diaphragm should form a check valve. It's best to have a couple of 6" pieces of soft rubber hose to use for the next stuff (else you may get a little old engine oil/gasoline/soapy water backwash). You should be able easily flush water from the tank connection through to the carb connection. I just get a mouthful of clean water and apply to the little hoses. Then immerse the hose for the tank connection in some water and "pulse" the pulse line with rapidly alternating pulse from your mouth. When I tested mine this way, it easily pumped a surprising volume.

 

[GTSRider]

If you use an electric fuel pump, you will be hard pressed to find one that has low enough pressure rating to work with your carb. However you can buy a regulator to limit the pressure at the carb.

Have you checked the pulse line that goes to the pump? Could be plugged, disconnected or broken.




Richard

Good thought..... but every component in fuel tank, to fuel pump and carb, is factory new, out of box.
Eventually , I will figure this out, and post answer. ( see original post....100% new from fuel tank to carb )

 

[Richard001]

GTS rider, have you found and fixed the issue on you tractor?