Help!!! Engine doesn't want gas

[fc10a3]

she'll start and run great until whatever gas gravity fed into the engine has run out, then dies. Not drawing in fuel. If I disconnect the fuel line from the carb and turn to prime it will flow like mad, reconnect it and it wont at all. I've played with the fuel line positions to no avail, also changed fuel filters (that way I can see it filling) and run no filter, no difference. If I let it sit for 10+ mins I can start her up fine and run for a few mins then dies again. I'm stumped.

The floats are set, carb is clean, I even changed the needle position to 1 down (more rich) didn't make a difference. Help, I've got a huge bike run this weekend.

 

[drewpy]

you may have a blocked vent in the gas cap, try without it closed!

 

[fc10a3]

I did no difference, but thanks drewpy, any other suggestions?

 

[drewpy]

eliminate the tank altogether and fit a temp supply and see how far it runs for.

that way we know its either the petcock or crud in the tank

 

[chris]

also, make sure the vacuum hose from the carb boot to the petcock is still attached with no holes

 

[HoughMade]

When you adjusted the float height, did you adjust the travel too? This is often overlooked and I didn't do it until about my 5th trip into the carbs. There is a tab on the float that controls how far the float can fall when the fuel level drops. I think it should be adjusted so it allows the float to fall as far as it can without binding and without the needle falling out....of course this applies to the brass float. If you have the plastic one, I'll leave someone who has experience at that one to comment.