I have been working on a fuel starvation issue on my Joyner 250 now for several weeks with no results. So far I have rotated the tank 180 degrees, shortened the fuel line to about 6 inches, swapped out petcock and gas lines to 5/16", removed the in-tank filter, and installed a large inline fuel filter.

Here's the problem. After long up hill climbs or long full throttle runs, the gas line runs dry. It's as if there is a vacuum lock or some type of air back pressure that will not let adequate fuel come out of the tank. The fuel will not flow even when I remove the gas cap, but if I disconnect the fuel line from the carburetor, fuel flow is excellent.

I even primed the inline filter to capacity prior to completing my gas line connection, but after about five minutes of riding, the fuel filter was empty and did not refill.

This appears to be a common problem as I have seen several posts on Buggy News.

My questions are this.

1. Is the fuel system gravity fed, or is there supposed to be some vacuum to help pull it in?

2. If there is some vacuum, where is it created and how can I test it?

3. I understand that the Blade 250 has a fuel pump. Is this something that could be installed on the Joyner?

4. Could you possibly contact Joyner to see if they have determined a way to correct this problem?

I sure hope I can get this problem fixed soon. I love this Joyner, but this is about to drive me crazy!

Thanks for your help.

If fuel is flowing freely when you disconnect the fuel line from the carb, I would remove the float bowl at the bottom of the carb and check to see that the floats are moving freely. There is also a shut off valve that the floats operate, which can be removed and inspected to be sure it is working smoothly. Be careful...small parts.

THe float and valve move freely. I've checked it several times. But if the float or valve was sticking in the closed (up) position, that would not allow the gas line and fuel filter to drain I would think. The problem is the gas line itself is not refilling. THis seems it would be easy to correct, but I am stumped right now.

What has me puzzled with your problem is that the line goes dry. How is air getting into your fuel line if gas was flowing from the tank? So you have an empty fuel filter and it is empty after WOT?

That's correct. the fuel filter ends up dry, and does not refill. It will get just a tad of fuel in the bottom, but no where near the normal amount. I can remove the gas cap, jiggle the gas line, nothing helps. I've tried 3 different filters, a whole new petcock like the ones others here have made up, and replaced all the fuel lines with 5/16". I have cleaned out the tank, eveything I can think to do (except dynamite). THe only way I can get fuel in the filter is to partially disconnect the fuel line from the petcock, allowing fuel into the filter, and I assume letting the air being replaced to escape via the partially disconnected line. Thanks for any help.

I might be grasping here.....do you still have the charcoal filter lines attached to the gas cap? Can you post pictures...or send them directly to me?

From your desciption....THe only way I can get fuel in the filter is to partially disconnect the fuel line from the petcock, allowing fuel into the filter, and I assume letting the air being replaced to escape via the partially disconnected line.

Is is somehow building a vacuum in the gas tank? Enough to prevent the fuel from leaving the tank?

I don't know.......just trying to brainstorm.....


Glade

If your tank is full fuel, the only way air is getting in the line is through the vacuum petcock or though the carb fuel inlet. Since you already replaced the petcock, filter and lines, I suspect something is connected incorrectly on the carb (causing air to blow up the fuel line) or the carb has an internal fault causing the same condition.

Could you post pictures of your carb and identify where each line is running in your pictures? This will eliminate the connections and lead us to an actual carburetor problem.

Doon- I have disconnected the line from the tank lid to the charcoal cannister. I don't even get any flow when the tank lid is removed. I have also removed the original airbox and installed a K&N redneck filter, so the line that used to go from the charcaol filter to the airbox is also disconnected, as well as the line that comes from the air intake between the filter and carb. This weekend I also went ahead and disconnected and capped the water lines that go to the carb.

pgr- When you say vacuum petcock, are you talking about a petcock like the 150's use? This is a different type of petcock-simple gravity flow.

I will try to get pictures to you guys in a couple of days. I own a restaraunt so I don't have alot of free time.

THanks for all your help.

A standard petcock goes from the fuel tank to the filter and is controlled by valve that is turned on of off by hand. A vacuum petcock has an additional line off the engine and only allows fuel to flow when the engine is running.

Sounds like your vent in the carb isn't doing its job,
little rubber line hanging on the side the carb. Try
blowing through it with your mouth, (no air hose)
If you cant blow through it and hear air coming
through, than it might be clogged. Just a thought.