New member needs help with Kubota EA300

[Trim]

Yes, it was absolutely the valve retainer on the end of the pump that caused the problem. When I opened the pump, the valve, spring and crush washer came out. When I put them back in, it seems that I lost the compression needed to seal the pump cylinder which is sealed purely by compression between polished steel parts and the crush washer at the other end.

As such, the lift pump produced enough fuel pressure to fill the high pressure chamber on ever stroke no mater where the fuel rack was located. Therefore, the engine ran at full speed all the time.

E.M.D.W.