Doosan engine fails to start, needs purge every time, hot or cold

[Bostwick70]

I have a bobcat S650 at work, new fuel pump, new fuel filter, fuel lines replaced, fuel bulb replaced, fuel tank flushed. Once it's up and running it runs fine, but it won't start unless it's both primed and purged with the fuel bulb and screw on top of the fuel filter housing and then hit with a squirt of starter fluid; it doesn't matter if the engine is hot or cold. Both check valves are working. Doosan engine. Any ideas?

 

[flyerdan]

It's got to be sucking air in somewhere, I'd suspect every connection where there is a hose clamp.
If nothing stands out, I'd spray the hose section with some soapy water and look for bubbles before I opened the bleed screw. If the bulb check valve is good, the issue should be between it and the injector pump.

 

[demo guy]

It's got to be sucking air in somewhere, I'd suspect every connection where there is a hose clamp.
If nothing stands out, I'd spray the hose section with some soapy water and look for bubbles before I opened the bleed screw. If the bulb check valve is good, the issue should be between it and the injector pump.

I had the same issue on the same machine. I had cracks on the return line coming back to the injector pump from the injectors. It's right up on the engine so it got dry rotted and cracked. I also found the 2 connectors coming from the water separator to the back of the I jector pump were sucking air as well. Replaced fittings at the end of the line coming into the injector pump. These 2 things had me snooker for so.e time because they are hidden against the engine and behind the alternator, injector pump, etc, etc.