Noisy Oil Pump Operation
One cause for a noisy pump is a misaligned oil burner coupling. Try loosening the mounting screws slightly and shift the pump position until the noise is eliminated. Retighten screws.
Air in the inlet line can also cause noise. Check all fittings and connections for leaks. Tighten or replace any leaky fittings.
A humming noise can be fixed by installing a Silent-Flo anti-hum device.
For more information on oil pumps: