So I'm up here on Whidbey and my heater stops working. The heater is at least 30 years old and has been relatively trouble free till this year. I contact the local guys and they come to fix it. They replace the nozzle and the filter , furnace fires up and they split. The furnace runs for an hour or so then quits. Wont manually start either. Call them back they replace the fuel pump. Fire it up running like a dream, quits after an hour. They come back bleed the pump, observe crappy fuel. Fire it up runs like a dream for an hour. Back yesterday replace the filter and the nozzle again. I also suggested we take a look at the elevation of the pipe in the fuel oil tank. it was low so we cut it off to 9" above the bottom of the tank. Starts up runs for an hour then quits. I come back bleed the pump and the fuel is pink... looks sort of air entrained. So if anyone knows I have a couple questions. Is there an easy way of pressurizing a fuel line to confirm it will not leak air? What pressure should I try to achieve. How much does temperature affect fuel viscosity? I Have to get this thing running before I leave the island as the house is at risk temperature wise.... Any ideas? By the way I am replacing the furnace in the spring/ summer to a propane fired. I am just trying to limp through the winter. Thanks in advance

Check heat exchanger and chimney for being plugged might be getting too hot and shutting down.?? Good luck

Sounds like a fuel line/tank problem.

Sediment in fuel sits at bottom.
Furnace starts, feeding fuel.
Fuel draws for about an hour.
Sediment moves up into system.
Sediment blocks fuel flow, killing furnace.
Furnace stops, cutting fuel flow, sediment settles back down.

I think you are on it... thanks, sounds like suspended contaminants.

This issue shows up on Car Talk from time to time, but with them it's a aging gasoline vehicle engine. But a system's a system, and symptoms are symptoms.

Howard. Any interest in chasing steel tomorrow?

I wish I had picked up this message! I could have pulled it off..... maybe next time ...