You do not have the tools to fix this incorrect flame. A poor color means that the flame is not bright, almost white. You can easily add more air than necessary making the problem just as bad or worse with unburned fuel.Ask a burner technician to inspect and adjust the flame to factory specifications using a combustion test kit. The rumbling, and rattling will go away.
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Harold Kestenholz
http://www.heatpro.info