I given a Ryobi 410r cultivator all the diagrams I've seen show 2 lines going into the fuel tank; 1 to the carb and the other 2 the primer bulb. My tank only has 1 nipple .

you will have 2 lines at the tank. 1 is the supply line with one end having the fuel filter on it and sitting at the bottom of the tank. it generally runs to the inlet side of the carb. the output side of the carb usually goes to the primer bulb inlet, the last hose usually goes from the outlet of the primer bulb back to the fuel tank but only goes in 1/8 to 1/4 of an inch. it should only be in far enough to seal the hole and allow the fuel back in to the tank

If you need further help, I’m available over the phone at https://www.6ya.com/expert/kelly_69a0cf1b13789df1

when the primer buld is empty, when pushed it should push bubbles into the gas tank and when let go should draw fuel from the tank. the primer buld now when pressed pushes fuel into the carb and should not push back to the tank. when let go again it will draw more fuel from the tank. the inlet nipple on the carb should be the 3 oclock

The primer pulls fuel through the carbruetor
So take your return line from the carb. and hook it to the inlet side of the primer and the other side
of the primer bulb transtions into the fuel tank.
You know when you have hooked it up right when you press the primer it fills with fuel and dumps back into the tank.

here is a manual,Tim:

http://lawnandgarden.manualsonline.com/mdownloads/38dcb043-331f-461b-a08c-072d67fc76c0.pdf

here is a diagram:

http://photos.hobbytalk.com/showphoto.php/photo/34693

in a nutshell:
1 connect top carburetor line to short nipple on primer bulb.
2 bottom carburetor line to fuel line with filter (inside tank).
3 connect remaining fuel line that comes out of fuel tank to the large nipple on primer bulb.

Hopes this helped Tim

I see that this machine has a 2 stroke engine. These directions work on the 2-stroke engines of Sears trimmers. I've never seen a diagram but many explanations are out there.
The small diameter line out of fuel tank (has fuel 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. The shorter nipple on the bub has a line from it going to the metering chamber side of the carburetor. 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 the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank.

You are searching for part number 181558. It is a snap in primer bulb with a piece of fuel line.

need brand name of your unit, but reading what you have I will say that the thick one from tank goes to carb and the thin one goes from primer bulb to tank as a return, for fuel. need more info!!

IT SOUNDS LIKE A TWO CYCLE ENGINE TO ME. THE HOSE GOING TO THE PRIMER BULB GOES TO THE HOSE THAT SITS ON THE TOP OF THE TANK AND DOEST GO IN FAR AT ALL AND IS USUALLY THE BACK. THE OTHER HOSE GOES IN THE NID PART OF THE TANK OR THE PART THAT THE GAS IS AT ITS HIGHEST POINT IN THE TANK WHEN THE UNIT IS IN THE POSITION MOST LIKE IT IS WHEN IN USE USUALLY THIS HOSE HAS A SMALL FILTER IN THE TANK. THIS SYSTEM OPERATES ON PRESSURE. WHEN YOU PUMP THAT BULB, IT PRESURIZES THE TANK FORCING GAS UP THROUGH THE OTHER LINE TO THE CARB. IF YOU ARE SYING THERE IS A 3RD HOSE HMMM, THAT PROBABLY GOES TO THE MIDDLE PART OF THE CARB
REGARDS

go to
http://rds.yahoo.com/_ylt=A0geu6ltf.pJT1oAdBFXNyoA;_ylu=X3oDMTEzODk0aDZyBHNlYwNzcgRwb3MDMQRjb2xvA2FjMgR2dGlkA0Y4MjNfMTAy/SIG=13im1am46/EXP=1240191213/**http://www.cmsmallengines.net/oregon-c29/fuel-accessories/oregon-replacement-primer-bulbs.html

The linefrom the tank with the filter goes to the mixture inlet on carb. The fuel return goes to the suction side of bulb. The bulb outlet line goes to the tank. Hopes this helps