Petcock on fuel tank advice (-85 FJ1100)

[Fjotten85]

  I am a Newbie on self servicing. Have a -85 that have rested for 12 years in the shed.
To dismount tank i flipped lever to PRI (Prime) and noticed that all gas was flowing out through an overflow pipe/hose behind engine. Had to empty tank totally before separating the fuel lines. The PRI did not stop fuel from flowing.
Ergo I have a problem With the valve?

I have noticed the advice to secure the pipe by  wiring: will do so.
But I have tried to find out what to do.
Buy a New petcock? Not sure I would like to since I really do not know if the beauty even will start. The value of it is little.
Could anyone advice me what to do?

Buy a New petcock or change internals?
Will this kit help?
   http://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3AVacuumPetcockRebuildKit
or this
  https://www.ebay.co.uk/p/Yamaha-Fuel-gas-Tap-Petcock-Rebuild-Kit-Srx250-Fj1100-84-85/907135796
or both?

Please help...

[Pat Conlon]

The prime setting turns on the petcock so fuel flows all the time. This setting should only be used to prime carbs that have empty fuel bowls, thus the name "prime".

The "on" setting shuts off the fuel and only turns on the fuel when the engine supplies vacuum to the petcock.
The "on" setting is the normal setting for the petcock.
With the engine off, if you turn the petcock to the "on" setting, then disconnect the fuel line and if you have fuel still leaking out the petcock, you have a bad petcock.

Time for a new one.

[Fjotten85]

Thanks, Pat: I think I've got it totally wrong, since the old workshop guide told me to firstly toggle to "off" position: there is no such thing.
I did not check if fuel where dripping out when in position "on".
The correct thing would be to just remove the two fuel hoses when still in "on", and check for spil.
It have been in the shed with fuel for 12 years without leakage.

I will test my petcock first, perhaps OK?
Just change the o-ring and screw gaskets (and one screw: head ruined since stuck)

Still good that I noticed the Group warnings about loose fittings on the outlet. Thanks

[Pat Conlon]

The correct thing would be to just remove the two fuel hoses when still in "on", and check for spill

Sure thing, check for a leaky petcock with the lever in the "on" position.

FYI, there is only one fuel line from the petcock to the carbs. The second smaller line is a vacuum line which connects to the port on the #2 carb manifold. That vacuum should be tight with no leaks or the vacuum signal will not open the petcock or worse, intermittently open the petcock.

I hope you don't have rust in the tank. If so, that needs to be addressed. The gravity flow FJ's (84-87) do not run a fuel filter which impedes the flow, a screen: yes, a fuel filter: no. As such, any particles of rust from your tank will play havoc with your carb's float needle seats, fuel idle circuit, pilot jets, and needle jet.

The later FJ's ('88-95) have a fuel pump, so they can run a real fuel filter, those lucky dogs.

Plan on a disassembly and ultrasound cleaning on the carbs. RPM has all the goodies you need.

Kudos for resurrecting your forgotten FJ!