Combines 1680 IH Engine fuel pump

Dave, not sure on a 1680 but just went thru the same thing with my 1480. lift pump on mine was on left side of machine back by straw spreaders. It was bad replaced it still lacked power but fuel filter (primary) was now full. Ended up being the injection pump cost 1500cdn for reman from CNH. Oh ya if you do it yourself it's quite a treat. Weapon

Before you spend alot of money,had a friend with similar problem and spent all the money and still not fixed. Until we took the line from fuel tank to the shut-off valve off and little balls of "dirt" came out of line and had valve inlet 90% plugged. Cleaned out valve and line, and ran like new.