930 sucking air

[DCP]

My 930 periodically dies of fuel starvation when all three fuel filters become filled with air. It's not because the tank is near empty or running on a hillside. Rather it seems there is an air leak between tank and the primary filter. I've replaced filter gaskets and bleed screw gaskets to no avail. I can't find any fuel leak in the line - it justs sucks air. Is the primer pump likely to be the problem? Has anyone else dealt with this problem?

Thanks for your advice.

DCP

 

[petetx]

had the same problem with my 1030 replaced the priming pump runs ok now that was 2 yr. sgo

 

[STUDIEDIESEL63]

Hi,are you sure its an air problem?We have 2 930s and had this happen.Thought to it was "air"cause I was getting fuel through to the primary filter.But after 35+ yrs.the fuel tank valve assembly had gotten partially gunked-up with kinda smeary black stuff.Been probably 5yrs.for 1 and 2yrs. for the other since I cleaned them. Still will blow black smoke with the bestof them ! Good luck.

 

[Doc Larry]

Another possibility - if this has a fine mesh, non-replaceable primary filter, it might be clogged with accumulated varnish and gunk. You can clean most of it out with a mix of acetone and denatured alcohol. Dead moths, bees, and flies in the fuel tank can also clog things up!

 

[DCP]

Thanks. I"ll try your suggestion. I think I"ve ruled out the other possibilities since I"ve had the tank removed and cleaned and replaced the filament filters 2-3 times.

Cheers

 

[mEl]

i have seen the inlet valves in the primer pump body jammed full up debris starving the fuel system, remove the pump from the filter base and disassemble it and check for plugged valves, be sure to check both the inlet and outlet valves. they are in the body at the fitting where the inlet fitting goes in and also where the pump assy screws into the filter base.

 

[DKase]

Take the fuel line off at the priming pump. Fuel should gravity flow out at full flow of the line. If it does not there is a restriction in the line from the tank. DK