You did fit the belt with the 3 pump pulley wheel bolts loose? if not the pump timing maybe out.
Align Crank and cam pulley with marks, insert pin/drill and loosen 3 bolts on pump pulley.
Fit belt and tensioner, tension belt, ensure every thing still in alignment & do up pump pulley bolts.
Remove pin and turn over by hand 2 revolutions, check all marks align and pin can be inserted.
You can double check the crank position via the flywheel housing wadding bolt hole, look for cut out in flywheel.