Need help Bentone oil burner cutting out

jv131

Hey all any ideas as to what could be causing this cutting out in the video. Only seems to happen once each time the burner starts up then runs fine rest of the time.

Cleaned out the chamber and pipes and cleaned around the nozzle. trying to order a new filter and currently taking the pump off to inspect it for dirt and clean it. Can't find any oil leaks anywhere so not sure if it's an air leak or something else. Two pipe system to the oil tank in basement.

Hard to find parts where I am so any help is much appreciated!

https://youtube.com/shorts/yDGfGN1QaXA?feature=share

Grallert

Do I hear a slight change in burner pitch? I think it's definitely fuel related. I thought I heard what sounded like a restriction. but it could be the solenoid valve briefly closing.