Thermostat "false" start

[Hube]

I have a Honeywell thermostat "Magic stat 32"... (3 years old) Most times it does its job in cycling the furnace (forced air oil). But the odd time it will call for heat, the burner starts up, and will run for almost a minute, then it shuts OFF. At this point the burner has not been on long enough to let the fan kick in. A normal heat cycle is burner is on for approx 7 minutes with blower running approx 3 minutes longer. After about 25-30 minutes the the thermostat will call for heat and it will go thru the proper cycle. This annoying "false " starts only happen ONCE in about every 2 days ( 40 cycles) or so, but are annoying. Any one have any input to this puzzle? Thanx in advance, Hube