Gas and Oil Home Heating Furnaces - Riello Mectron 3 burner problems

I have a Riello Mectron 3 burner on our furnace. We recently had this serviced by a licensed burner tech. Within a couple weeks of this service I have noticed exhaust fumes around the front of the burner as well when the flame ignites, there is a small explosion in the fire box.
My question, is there a problem with the oil/air mixture that may be causing this, or is there a possibility that the electronic ignitor?
Any suggestions are welcome,

Thanks

I would suggest that the cause of the explosion you're reporting (and probably the smoke as well) is "delayed ignition", which could be due to the electrodes having been set a bit too far behind the nozzle, so the oil/air mixture is not being ignited as promptly as should, allowing some accumulation of it, which results in the explosion and subsequent smoke you see when ignition finally occurs.

Yes the primary could possibly be the reason (you call it the electronic ignitor), though I doubt it. Check the above first.

Riello set up specs are entirely different from American (Aero, Beckett, Carlin, Wayne) style burners. I suspect there to be a problem with the way it is set up or adjusted. Call the company back & ask them to send out someone familiar with Riello burners. Riellos in general ignite a little "harder" than American style burners but you should not hear a small explosion much less have smoke from around the burner. If the tech has any problem setting up the burner, he/she can call Riello Tech Support toll free 24/7.

I have a Reilo burner on a oil furnace, forced air, and the noozle continues to leak, I have replaced the noozle twice and it continues to leak, not sure at what location, but this causes the sound of the furnace vibrating quite loudly when igniting.
Could someone please help me with this.
It all started after a cleaning last winter(07-08) adn I called the tech to return and he replaced the noozle, which made no changes. He promised to return, but after many attempts, he has not, maybe it good he didn't.

Thanks
Grinner26

I wonder if the threads in the nozzle adaptor aren't stripped.
Is there any external oil leakage? Are you sure the presumed excess fuel is coming from leakage & not an incorrect nozzle or the burner being set up incorrectly?