Fuel pump constantly running

[infinity999]

Well I have been trying to troubleshoot my bike for months now. Most of the time it only wants to idle on 2 cylinders, today it actually idled on all four.

I believe the problem now may be an issue with the carburetors. Every time I cycle the key the fuel pump for 3-4 seconds which is a lot longer than the couple of clicks or none that it used to. Also, I listened with a long screwdriver and the pump is constantly running when the bike is idling. If I take the fuel line off the carbs and plug it with my finger the fuel pump doesn't run when cycling the key. I would say with almost certainty that there is an issue with the needle valves or those O-rings are leaking from the needle valve seats? The needle valves were replaced recently. Any suggestions are appreciated.

 

[marsmax85]

not an expert but that gas had to go somewhere check oil for leak down, Make sure thats ok first drain oil. People talk about a diaphragm in fuel pump that gets dislodged ?

 

[infinity999]

Yeah I have already opened the fuel pump, didn't see anything floating around. My pump looks a bit different than the one used as an example here. My bike is an '03, maybe newer than the one used. There is nothing wrong with the pump if I can plug it with my finger and it doesn't run when cycling the key. I am 99% sure it's the carbs. Something is leaking internally and dumping gas down a couple of the cylinders.

 

[dannymax]

Remove the carbs and place them beside the bike....extend the fuel line to reach and cycle the pump.

 

[SpecOps13]

Run the bike for a couple minutes. Drain the Carbs into a light colored paper cup and look for any
rusty trash in each. It happens. If you find nothing, Dan-o made a good suggestion. Atleast with the
carbs off you'll be able to see which carb or carbs is the issue.

Good Luck, carb problems SUCK.

 

[infinity999]

Yeah I'll do that in the next few days. I think I can run the fuel line to each carb with them still on the bike.

I doubt there will be any rust coming from the tank. I live in Vegas, very dry climate and the bike spends very little time outside. Thank you for the suggestions, appreciate it!

 

[dannymax]

Yeah I'll do that in the next few days. I think I can run the fuel line to each carb with them still on the bike.

I doubt there will be any rust coming from the tank. I live in Vegas, very dry climate and the bike spends very little time outside. Thank you for the suggestions, appreciate it!

That won't give you definitive results...it there's an internal leak gas will just drip into the intake runners.

Put the carbs on some cardboard, charge the line then check the cardboard.

 

[alorio1]

Only thing I can add to dannymax's suggestion is to have carbs sitting level when you do the test.....

 

[jfeagins]

You mention looking inside the pump and NOT seeing anything floating around in there loose. Did you positively identify that the small diaphrams were in there, and that they were correctly in place?

With the fuel line off, and your finger plugging it, when you cycle the key to ON, that pump may only pump a few times before timing out anyway. It won't ever sit there and run constantly w/o the bike actually running. If it were working correctly, I'd think it would have been fighting your finger to spit some gas. I know it don't take a lot of finger pressure to hold back 3-5lbs of pressure, but that pump should have been trying to make a mess, none the less.

 

[infinity999]

My pump didn't quite look the same as the one that is posted on this site. I did see a couple of rubber diaphragms and they looked to be in place. If they had fallen out I would have seen them for sure when I opened it up.

Yes, with my finger plugging it there was definitely some force and a bit of fuel was seeping out around my finger. The pump only runs constantly when the engine is idling and it does run for 3-4 seconds every time you cycle the key. I think I have ruled out any issues with the pump.

 

[jfeagins]

So, the ongoing problem you are having now is that the bike often idles on just two cylinders?

Does the bike open up and run OK at city/hwy speeds?

Have you checked voltage during idle? Voltage while revving?

 

[dmax1]

If the carbs are leaking into the runners you should check the oil and see if it has been contaminated by excess gas. you may be washing down the combustion cylinders of of your bike . :confused2:

 

[infinity999]

Yes, the bike runs fine above idle, all cylinders fire then. I have check the voltage and it's fine. If the floats are correct, which I think they are, fuel has to be getting past the O-rings on the needle valve seats. I'll find out for sure this weekend.. I hope the crankcase isn't filled with fuel, that wouldn't be good!

 

[tugla]

if its running or cycling everytime you turn the key yes it must be going somewhere I would think you would see or smell it flooding. did you check the oil? also don't want to be gas washing the cylinders.
now you say it idles and run fine at rpm correct?

one time I had my pump also constantly run when cycling the key. what was going on was the pump since it stops running after a cycle time it didnt run long enough to first prime the fuel line and fill the bowls correctly..... I figured this out and took the pump off filled it with fuel and the line to carb then when I turned the key it filed the bowls and would shut off and not cycle every time key was turned.... basically it lost its prime.

pump does run while bike is runing since fuel level will drop it keeps it topped up.

so not sure if this is pertinent to your issue as I quite don't see whats going on with yours. u might want to remove the carbs and hook up to line for visual confirmation as Danny sugested.... might be best route.

 

[tugla]

How did ou make out with this....

 

[infinity999]

Well I got the carbs off the bike and split into pairs yesterday.. Of course that took all of about 15 mins. Getting good at it now.. I was being lazy today so I dig into it tomorrow. Figure I'll hook up the fuel to each carb individually and see what the pump does. Focusing on carbs 3 & 4 of course. Thanks for the help everyone!

 

[tugla]

interesting diagosis technique.... cool well have u determined its not shutting off fuel mean it is overflowing.....is it flooding at idle with fuel pissing out of carbs ??????? u never mentioned its flooding externally yet.....

 

[dannymax]

----

 

[dannymax]

Nope, never any flooding externally. I just hooked up carbs 3 & 4 individually and of course it takes a couple of key cycles to fill up the bowls. After that I can turn the key on and off and the pump isn't running! Now I'm confused. Maybe it's one of the hoses doing something weird? I did hook up a different line from the pump to the carb.. I also hooked up carbs 1 & 2 (together). The bowls fill, then if I cycle the key the pump doesn't run again. Maybe it is an air leak in one of the lines? Or the line that goes from the pump to the carbs. Guess I should go buy some clamps..

As long as the carbs are off, you have nothing to lose by re-assembling them, hooking the fuel line up and trying them beside the bike....I got a feeling the pump will work fine.

 

[infinity999]

Looks like the time is a little off on these posts. Must be something with moving the site. Yeah, I hooked all 4 up and the pump seems fine. Not sure what's going on, maybe the clamp wasn't tight enough going from the pump to the carbs? What is up with that weird clamp anyway? Can't a regular clamp fit there?

Nope, never any flooding externally. I just hooked up carbs 3 & 4 individually and of course it takes a couple of key cycles to fill up the bowls. After that I can turn the key on and off and the pump isn't running! Now I'm confused. Maybe it's one of the hoses doing something weird? I did hook up a different line from the pump to the carb.. I also hooked up carbs 1 & 2 (together). The bowls fill, then if I cycle the key the pump doesn't run again. Maybe it is an air leak in one of the lines? Or the line that goes from the pump to the carbs. Guess I should go buy some clamps..