Problem with fuel pumping on diesel parking heater

[HandyNotHandsome]

I have a Chinese parking heater that I've been fueling with old heating oil, run through a couple filters and a separator. Recently it stopped pumping (no clicks). I took out the pump and rinsed with some WD40, and saw that it pumped just fine when I applied 12V. So I put it back in, and now the pump seems to work, but it's not actually moving any fluid - there seems to be some obstruction past the pump. If I disconnect the pump outlet, it sprays oil just fine, but if I re-attach the outlet, it clicks but does not move fluid.

Can anyone suggest a likely cause or location of the obstruction, and/or fix, before I dive in and take this thing apart?

 

[whateg01]

When you say you disconnect the pump outlet it sprays just fine, do you mean the pump pumps ok? That would point to the jet, or whatever they are calling it, imo. Maybe you aren't filtering the heating oil as well as you think you are.

 

[WildBill]

I have a Chinese parking heater that I've been fueling with old heating oil, run through a couple filters and a separator. Recently it stopped pumping (no clicks). I took out the pump and rinsed with some WD40, and saw that it pumped just fine when I applied 12V. So I put it back in, and now the pump seems to work, but it's not actually moving any fluid - there seems to be some obstruction past the pump. If I disconnect the pump outlet, it sprays oil just fine, but if I re-attach the outlet, it clicks but does not move fluid.

Can anyone suggest a likely cause or location of the obstruction, and/or fix, before I dive in and take this thing apart?

It could be in the line, the little metal section of pipe going into the heater, or most likely the small screen it sprays through is clogged from soot. Which is very likely when using old fuel. If you pull out the glow plug you can see the screen down in the hole. You need a little hooked piece of wire or something to pull it out. Make sure the new/cleaned one gets pushed all the way back down in the hole. You could also try blowing air into the metal section of fuel line, it should pass through into the heating chamber easily.

 

[WildBill]

There are also dozens of youtube videos on doing maintenance and repairs on these.

 

[HandyNotHandsome]

Found the problem... I opened up the heater and took a look where the fuel enters the heater. Due to (IMO) a really bad design, the combustion air, the fuel port, and the exhaust are all located at about the same spot with perhaps 1/4" of separation between them. Due to this, it looks as though the plastic fuel line got hot enough that the spring clip holding the rubber tube onto the plastic tube compressed the fuel line closed.
I just clipped off the bad section of tubing and reconnected, and tried to route the line a little better. I may come back and put a short piece of metal tubing in the area near the exhaust to prevent repeat problems.