Have a 1984 mobile home intertherm furnace it takes like 2 minutes for the blower too come on after furnace is heated up already my heat is going rite out the roof vent before turning on.. blower turns on way too late help!!

If it is the older style furnace, there is a limit switch that controls the blower. Follow the power leads from the blower to the relay that controls it. Follow the coil wires from the relay to the limit switch. Start with cleaning it. If that doesn't help, take it out and go to a HVAC or electrical supply. The guy at the counter should be able to match it up. Won't hurt to have the model and serial number of the furnace with you.