petcock positions

[ratgs81750l]

ok so on the petcock which way is which, ive got mine in the down position which seems to cut it off is this off or what which way is prime and on ..thanks guys

[khardrunner14]

My 81 g550l is like this:
up and right = prime
down = run
up and left = reserve

maybe that helps

[ratgs81750l]

ok so in the down position fuel should flow when the engine is on ????

[Nicholaschase29]

Yes, when the engine is on if everything is in working order with the vaccume line attatched. That is if your petcock is like his. mine is and i have a 85 700EF
in prime it should just flow out with the engine on or off. and reserve should flow with the engine on, like the on position.

[khardrunner14]

Yes, that is the standard on position. There is a vacuum stop that is controlled by the engine vacuum. If you are not getting fuel there is a good shot the petcock is toast.

Here is a way to check...
-take the tank off and leave the lines connected to the petcock (or connect new lines)
- put the petcock in the on position
- put the end of the fuel line in a glass jar or some other suitable container
- suck on the vacuum line

Fuel should come out of the fuel line and fill the jar. If the seals are toast you will get a little gas in the mouth...don't swallow :-D !

- Put the petcock on "prime" and you should have fuel flowing freely.

[khardrunner14]

Yep. It is.

[ratgs81750l]

woohoo...so after the vacuum test i find out either A. i dont have enoughh hot air in my lungs to pull a vacuum on the line or B. the petcock is bad because the gas only flows in prime and reserve no matter what i do well a new petcock is on order ETA-this friday...i find A hard to believe because im full of hot air...

[ptm]

You don't have to suck hard. Just enough to move the diaphram. I'd use a clear hose so you can see the gas coming and avoid getting it in your mouth. Even if you don't swallow, some is absorbed through the tissues in your mouth which is a Bad Thing...

[ratgs81750l]

yea i used a clear siphon hose but nothing would budge got fumes but that was it maybe its bad after all