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The bulb will have two connections one will be pressure the other will be suction, the suction goes to the car and the pressure goes back to the tank, so the bulb pulls fuel from the carb, into the bulb and back into the tank, the hoses are just an interference fit in the the fuel tank.

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The (clear) fuel intake line runs from the top of the carburetor (straight nipple) and goes to the short post on the back of the primer bulb. The return line (blue) comes from the long post on the back of the primer bulb and goes into the bottom of the fuel tank.
One is the high pressure line, which sends fuel to the injectors. The other is the return line, which dumps fuel that the injectors don`t use back into the tank.
The operation of the primer bulb is quite simple. When the filled bulb is squeezed, the pressure closes the inlet valve and opens the outlet valve which then sends the fuel supply to the engine.
Most vehicles have rubber fuel hoses connecting the fuel pipes on the chassis to the fuel pump or carburetor on the engine. Rubber hoses are flexible and can be cut to length as required, but they have a tendency to perish over time and can rub through if not properly secured.
Metal, Rubber, Braided, or PTFE Lined

Fuel Lines can be made from many different materials. If you plan to race, be sure to check the rule book for your track or sanctioning body. Using the right material the first time will save you time, money, and headaches.

Fuel Pumps & Lines

Located in the fuel tank, your fuel pump moves gas from the gasoline tank to the engine. The pump creates the pressure needed to move gas from the fuel lines to the engine. While your car is running, the fuel pump is in constant motion moving fuel until your vehicle starts to run low on gas.

The supply hose is connected to the fuel filter. The return hose is connected to the top of the fuel tank.
In gasoline cars in U.S., the return line was the fuel flow outlet of a back-pressure regulator on the fuel injector rail on top of the engine. It flowed back into the fuel tank.
The purpose of the primer pump is to pump sufficient fuel from the supply tank to the engine and particularly to the injectors of a diesel engine to enable the engine to be cold-started without excessive use of the electrical system which normally operates the fuel pump.

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Need to change gas line tube – Craftsman Convertible 25cc. Gas Line Trimmer

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Gas line routing – Poulan Wild Thing 2375 18" Gas Chain Saw 2.5 Cuin
ANSWER : Try going to a local hardware store and ask them about gas routing for chainsaws. If that doesnt work then I suggest to send the chainsaw back and have them replace it.

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I need to replace to fuel lines on a Craftman 32cc trimmer. The old ones cracked apart. 2 of the lines look like 1/8″ OD one line looks like 3/32″ OD. Larger line looks like it hooks to filter, Smaller line to a fitting in the gas tank. I am assuming the smaller line ges to the primer inlet. My question is the lines penetrate the bottom of the gas tank. How do they seal. How do I install the filter and the fitting. I am assuming to thread the new lines in from the bottom of the tank and pull through the gas cap hole. Then I attach filter or fitting and pull back through. So do I pull the line so as to create a seal from the swell caused by the fitting/filter?
ANSWER : Depending on the brand of line you use, Tygon line is self sealing but seems to shrink faster then factory supplied because of the ethanol in the gas. The stone gas filter is designed to fall to the lowest part of the tank, not stop the line from falling out.

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Gas lines crumbled and don’t know how to route new lines correctly
ANSWER : The small diameter line out of fuel tank (has filter in-tank on end) connects directly to the side of the carburetor that has the fuel pump….that is the cover without the hole in it. Other larger diameter fuel line out of tank connects to the longer nipple on the external purge/primer bulb. The bulb “pulls” fresh fuel from the fuel tank to the carb and then out of the carb to itself, where it then “pushes” any air/old fuel back into the fuel tank. The remaining larger diameter fuel line in this setup goes from the metering chamber (has cover with writing on it and a vent-hole) side of the carburetor to the smaller nipple on the purge/primer bulb. Again, on the primer bulb, the longer nipple has a line going directly from it to the tank. This is the return line. The shorter nipple on the bub has a line from it going to the metering chamber side of the carb. If the purge/primer bulb is on top of the carb…small line from carb body to small hole in tank with filter. Larger diameter line goes from the bulb on the fuel pump side of the carb to the larger hole in the fuel tank where sometimes the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank. Otherwise, the line should enter the tank for about 1/2″ or so.

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Ryobi gas I changed the primer bulb and gas lines on my machine and now it doesn’t get any gas to the carb. The primer bulb pumps it up, when i take the gas line loose at the brass fitting on the bottom of the carb, gas spews out. If I pour gas straight into the carb, it will start and run until that gas is gone, then it goes dead. It’s like the gas goes to the fitting but won’t go into the carb, even if you pull the trigger like you were running the thing. Any suggestions? Gasless
ANSWER : Check the fuek lines for hole and leaks, check the fuel filter and clean if necessary. remove the carbuerator and inspect the gasket; it should be soft and flexible, if it seems hard or brittle replace it. clean the carb with carb cleaner sray (available at any local auto parts store) and compressed air. make sure you get inside the small fuel rail holes. also check the primer bulb for pin holes and proper seating/seal. if that doesn’t work have the carb repaired at a service center or replaced.

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809117565 bulb primer not priming
ANSWER : Probably needs new fuel lines to/from and in the tank. Have you been using ethanol gas? It eats up the fuel lines on 2 cycle motors. After you get it fixed, use only pure gasoline. I’ve had to rebuild two of mine so far!

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My tractor stalls like it is starved for gas although the gas tank is full. I,ve changed the fuel filter and the gas cap. I’ve cleaned out the gas tank, gas lines, and the carburetor bowl. The problem seems more acute when the gas tank is full or near full. At this time to alleviate the problem, I blow through the gas cap and the fuel filter fills with gas and it runs good again. But as soon as the fuel filter has no more gas, of course, it stalls until I blow on the gas cap. As the tank gets down to about 1/3 full, the engine runs OK. What else could cause this condition?
ANSWER : I had a similar problem with a sears tractor. close to the carbarator is a rectangle box with a rubber hose going to the engine block – remove the hose and spray carb cleaner in the hose wait a few mins and try again – its a vacuum for the carb

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Fuel line diagram for craftsman gas blower – Craftsman 25cc Gas Line Trimmer

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