Fuel leaks from top of accelerator pump

2 replies to this topic
  • hattackk

Posted January 27, 2015 - 10:43 AM


Anyone have an idea why fuel would be leaking from the rubber boot area where the rod goes into the AP? Only leaks when you twist the throttle. It has a new diaphragm. 


99 yz400f

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  • grayracer513

Posted January 27, 2015 - 11:40 AM


The only reason it could leak from there is if the diaphragm has a hole in it or, possiibly. you may have it installed wrong.  Fuel is supposed to be confined to the pump cover, below the diaphragm.  In order for it to get out around the shaft, it has to get past the diaphragm.  No more complicated than that.

  • hattackk

Posted January 27, 2015 - 07:28 PM


Thanks Grayracer, the diaphragm is new but could be defective. I'll check it tomorrow for a tear or leak. There is a lip on the diaphragm that sits in a channel maybe it isn't sealing there.

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