No fuel what in the carb can cause a fuel filter to go from full to empty after 15 miles of driving? I know its not the tank, gas cap, petcock, fuel lines, or fuel filter.

If you have the fuel petcock (valve assembly attached to bottom of fuel tank) to either 'on' or 'reserve' and no gas is flowing through the fuel line - the most likely culprit is either a) petcock itself is clogged or the filter inside the tank that is attached to petcock is clogged or b.) you could possibly have a malfunctioning fuel cap. The fuel caps are usually vented to allow excess pressure to vent off. If for any reason that fails - then basically it becomes a vacuum issue. You could try loosening the fuel cap - not completely removing - just loosen and see if the flow starts - if so, it's your cap. (Some you could shake to test function - you would hear a rattle if the mechanism was still good - not all though). If loosening cap doesn't help and you're sure you're in correct position - you'll have to remove that assembly. Two screws or bolts usually hold petcock to fuel tank. Remove those two bolts, usually a rubber o-ring type gasket or another type of gasket - and a tube/filter is attached to petcock. As you remove you'll see exactly what I'm talking about- that's actually your fuel filter/reason there is usually not an external fuel filter. IF it's not clogged - the issue lies within the petcock itself. Some are able to be disassembled, cleaned and reassembled - if not/replacing would be only option. These tips are assuming that you've removed fuel line from carb - if not, please check with fuel line removed - if you're still hooked to carb, but are sure there is no fuel flow - and fuel does flow when unhooked/clogged port to carb or your float is not functioning properly allowing fuel to enter carb. All The Best & Good Luck

Everybody had a crack at this problem, another thing would check is these engines sometimes have a primary fuel filter inside the tank itself. Drain the fuel and gently blow compressed air back through fuel line towards tank then rinse the tank out with fuel, refill and try run engine again

Pull gas line from gas tank to carburetor/injector/throttle body.

If carb, turn on petcock, allowing gas to flow into a gas can.
Remove gas cap to improve/increase flow.

If injected, turn on ignition to cause fuel pump to turn on, flowing fuel under pressure into gas can.

Remove the gas tank shut off valve and clean it or replace it. The filter in it must be clogged.

Hmmm, strange. Two things to check. Since you didn't tell me what year or model bike you have, I'd check the petcock and the tank vent in the fuel cap. The fuel cap is simplest test. Ride the bike until it starts bucking and then loosen the fuel cap. In the case of a Softail with two caps, loosen the left side cap and see if this remedies the problem. Don't that the cap completely off as you may wind up with a lap full of gasoline. If your bike is a model later than 1996, your bike is probably equipped with a vacuum operated fuel petcock. Make sure the vacuum line is connected to the backside of the petcock and the backside of the carb. To test the petcock, pull the fuel line off the petcock, turn the igntion on and spin the engine with the starter. You should have a full flow of fuel from the petcock. If not, replace the petcock.

Good Luck
Steve

Could be the fuel pump, the petcock screen,the fuel filter, the fuel regulator, or the float inside the carb.

Just start with the petcock and rule out one item at a time

Loosin the fuel cap may be a clogged air passage in cap if runs good find out why passage plugged ..check petcock strainer / filter in tank..or petcock obstructions or if vac operated petcock loosing vac,,,???

It may indeed be out of gas. You can have a full tank of fuel and be "out of gas" in the carb. The culprit could be the vacuum operated petcock. The petcock has a diaphragm in it that is opened by engine vacuum. If that diaphragm is not functioning as it should, no gasoline gets to the carb.

To test the petcock, reach around behind it and feel for a small vacuum hose. Unplug this hose and replace it with a hose you can **** on. Using your mouth, **** on the hose with the fuel line disconnected. You should see fuel flow out of the petcock. If not, you must drain the tank by loosening the petcock and allowing the fuel to run out of the loose petcock. Use a large funnel and an empty fuel container to catch the fuel. Once the fuel tank is empty, remove the petcock. Take the plate on the back of the petcock off by removing the four small screws. You'll find a diaphragm, a small spring, and a needle. Hold the diaphragm up to the light and stretch it gently. If you find a hole in the diaphragm, replace it. Check the petcock for obstructions by blowing through it. Reassemble the petcock and test it again.

Check the hose that supplies the vacuum to the petcock. It comes from the backside of the carb and runs upwards to the VOES switch and then reduces in size and goes to the petcock. Make sure it's connected and has no holes or cracks in it.

If everything looks alright, replace the petcock, connect the hose and try to start your bike again.

These petcocks are notorious for giving problems. I always recommend that the vacuum operated petcock be replaced with a high quality manually operated petcock such as a Pingle. They're expensive and require you to manually turn the gas off like the "old school bikers" do but they won't leave you stranded out of gas with a full tank of fuel.

Good Luck
Steve

Could be that the gas tank cap is not venting properly and is causing a partial vacuum in the tank. Next time this happens, open the gas cap and see if fuel flow is restored. If so, take the cap off and see if it needs cleaned/derusted.

Hi Dave, it sounds crazy, but try this. Check your gas cap. It could be clogged, causing a vacuum to occur in the tank, and therefore not allowing the carb. to take on gas. It usually take 10-15 min. for this to occur. The next time you run the mower and it starts to stall out, loosen the gas cap and see if it begins to run again. If it does, then you know that the gas cap is clogged.

Jim