Another fuel pump Issue???

[Ost85vmax]

So I have read all the numerous issues regarding fuel pumps that never stop running during the initial start up. This is my issue also. I have taken the fuel pump apart and low and behold the rubber seal that is spoken about was out of place. I replaced it and it seems to help a little??? Maybe? The bike runs fine so I have pretty much overlooked it until I had time to dig into it more. Well nos that time I guess.

I am hoping that someone can run me through a checklist of things to look into. I guess I wil take the fuel pummp out again and look things over but since I have done this does anyone have other areas that I should focus on? Any aftermarket fuel pumps to recommend? Also if the pump just keeps running, or running thorugh the startup sequence (it does stop at after the 5 sec time) but where is the gas going? Is ther somewhere I should be looking for it to be overflowing?

Thanks!!

 

[wildweasel_pt]

It goes to fill the fuel line and carb bowls (don't forget the tank is below carb level). When bike sits for a long time the fuel comes back in the line needed to be primed before starting the bike again...

 

[Ost85vmax]

It goes to fill the fuel line and carb bowls (don't forget the tank is below carb level). When bike sits for a long time the fuel comes back in the line needed to be primed before starting the bike again...

Thanks for the info. I understand what its doing but dont understand why i could cycle the key on and off 100 times and the pump will cycle the same everytime as if the bowls are empty. I dont see any fuel anywhere either.

 

[[email protected]]

Check this out
http://www.vmaxforum.net/showthread.php?t=8775

 

[wildweasel_pt]

Thanks for the info. I understand what its doing but dont understand why i could cycle the key on and off 100 times and the pump will cycle the same everytime as if the bowls are empty. I dont see any fuel anywhere either.

That may be a problem with the fuel pump or the fuel is draining inside the intake. Do you get exhaust pop when starting if engine is at working temperature?

 

[[email protected]]

Check this out
http://www.vmaxforum.net/showthread.php?t=8775

Guess I should have paid a bit more attention to the first post. It sounds like you already tried this.

I have heard a few guys mention that their pump runs on and on. IIRC it came down to a sticky float or leaking float needle/seat. I have heard of fuel coming out the exhaust from the pump running so much. You could also check you oil to see if it smells like fuel.

If there are no signs of fuel going anywhere it may be a good idea to test the output of the pump and see if it is working correctly.

 

[Ost85vmax]

All this info is very helpful! Thanks for the help from everyone! Great community here!

I have had the pump apart i have run it through its 5 sec startup procedure at least 15 times in a row to try and find gas leaking out somewhere and nothing gives. Guess i will look at trying a new pump. The only thing i can figure is the rubber piece in the pump continually gets dislodged from where it needs to be.

 

[wildweasel_pt]

Being said that the diaphragm keeps getting dislodged i would say that the pump is not building enough pressure to stop it from clacking everytime. If you run it in high revs i may think you can get fuel starvation due this problem... Im leaning to having to replace the fuel pump also. You can always check if the output pressure is according to specs. thats a low pressure fuel pump so i'd say around 4 psi but you can find that info online using the fuelpump part number. I think its a Mitsuba. Check service manual...

 

[Ost85vmax]

Thanks. Every once in a while i do get a little hesitation at high rpms so this sounds right.

Great help here! Thanks.