Furnace not lighting

[Dan DeBruin]

Have a Suburban sf-42 furnace. When I went to start it today to get ready to go, the fan came on like is should but then when the gas was supposed to light, I could hear it light but went out immediately. I took off the outside cover and it started and ran for an hour or so, just like is should. It is back to not starting again.

I am looking for some trouble shooting or ideas about how to fix it.

Thanks

[Ray,IN]

How long since it has been cleaned and serviced? Any obstruction in the burner area will cause problems, like wasp nests, muddabbers, spider webs/nests-who BTW love the smell of propane.
I've read of the access door causing problems by restricting intake combustion air. The bug screens can cause this air restriction too, the furnace mfgr, even discourages their use.

["007"]

I agree with Ray look for air restriction clean burner tube and check flame sensor for carbon build up.

[justimagination]

........Try and get an airhose and blow it out real good, you will be surprized how much dust and mud dobber nests will come out. Ligt the stove as well(all burners) to make sure there is no air in the system, good luck,
David G.