My 8 year old burner motor is dripping oil from the bottom of the grey(plastic?) part of the Beckett AFG burner. It appears to be starting higher up at the split line between the two grey parts. It amounts to about a drop a day. The guy who serviced my furnace told me it's because the high stack temp(720) caused by the power vent location back pressuring the motor. Does this make any sense? This is the same guy that wired my humidifer to run 365 days a year.
Thanks

Could be a
Bad pump seal.
Split nozzle adapter.
Spit back from burner (residual after burning)
Incorrect nozzle spread.
Post nozzle drip. ( bad check valve in pump).

No matter what it is one drop per day is liveable.

Note if you have a 720 degree F stack temp something is wrong.
You are sending a boat load of heat up the chimney.
Your oil bills have to be high.
Contact a qualified contractor that has a fire eye tester or something else that does the job and get your burner setup correctly. They need to check the smoke number, temp, CO content, and draw over the burner.
Something is wrong with this picture.

hvac1000, thanks for the quick reply. I'll call the guy back. It's a family(not mine) business that been around for 60 years. The heir apparent son-in-law thinks he knows it all. The temp used to be around 460-480.