Worcester boiler black smoke after service

[labreole]

I have changed the jet on this boiler twice, cleaned out the combustion chamber and adjusted the oil pressure with a gauge. I am feeding oil from a temporary container at the side of the boiler. Am I correct to suspect the oil pump. The boiler runs for a while and then the green indicator light flashes from green to red/green he eventually to lock out. There is substantial black smoke that suggests incomplete combustion. Is it worth adjusting the air supply since I have no gas analysis gear.
This boiler had not been running for several years and was empty of both water and fuel.
any ideas please

 

[Terrywookfit]

If nozzle is correct size and oil pressure ok it must need more air.
slowly open air shutter until no visible smoke is seen..

 

[labreole]

Thanks for that, I have opened it two units from 3 to 5 but maybe the dial has been altered, so will keep opening.