Injector Pump 990

mart990 · Feb 17, 2015

I have a 1964 David Brown 990 Implematic. I was clearing snow and it died out as if it ran out of fuel. Checked lots of fuel in the tank. On the injector pump I am getting fuel from the lower bleeder screw but not from the upper screw. Is there a filter screen or anything that could cause a blockage in the injector pump. Anybody have a diagram of the pump. Any Ideas?

thanks

Dieseltech · Feb 18, 2015

Does the hand primer deliver good flow through the lower bleed screw with NO air? Injection pump will not work if any air is present, the upper screw can be bled later while running, it removes trapped air to prevent rusting governor parts. Can you get air free fuel to the injectors with the line nuts loose while cranking engine? You may have a dead feed pump, or a stuck metering valve in the injection pump.

mart990 · Feb 18, 2015

I didnt find the hand primer worked. Turning the tractor over gives a good stream with no air from the lower bleed hole. I have not undone the lines at the injectors yet. I guess thats the next step, undo one crank it and see if fuel with no air. Is it a real high pressure at the injector?
thanks

RGMartin · Feb 18, 2015

Just loosen the injector lines a half turn or so. No need to remove them. As soon as you get a nice rhythmic drip at the nuts you can tighten them up and try to start it.

Injector Pump 990

mart990

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Dieseltech

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mart990

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RGMartin

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