The problem goes like this. Thermostat calls for heat, burner starts and runs for a minute or so and shuts off. After burner shuts off, the blower starts and the burner starts again until the thermostat reaches temp and the burner shuts off blower contiues to run until the low temp limit is achieved. Would this be the fan/limit control? I've tried making changes to the fan/limit on-off points but there is no change.

labman

Certainly sounds like that is where the problems is. The limit switch that shuts the burner off may be tripping before the the one that starts the blower does. There may be enough residual heat to then trip the blower switch, and when is starts, it cool the burner switch and it starts. I would think turning down the blower switch would have done it. Have you tried cleaning the switch so it can heat faster? Maybe even remove it and clean the the base and where it mounts.