Roosa-Master DB2 Injection Pump problem

(quoted from post at 10:36:59 05/18/15) I have a Ford Powermaster 861-D I'm having fuel delivery problems with. I've had the tractor about 3 years now and I use it occasionally to grade gravel, plow a small garden, haul firewood around, give the kids rides, etc. It started and ran great when I got it, but did leak a little fuel from somewhere on the injection pump {never really looked into it b/c it wasn't much and didn't cause any problems}. [b:5176b95cc2]The problem started with the tractor suddenly not re-starting after it'd been run and got up to operating temp and was shut off for a minute or more until it cooled all the way back down, then it would start fine again.[/b:5176b95cc2] I went through all kinds of tests / attempted fixes, new battery & cables, fuel filter, checking for clogged fuel line, reading it could need a head gasket, etc. It sat all winter and now it won't start at all. I'm now fairly sure this problem stems from the Roosa-Master {now Standyne} DB2 injection pump itself.

Most recently I tried to bleed the injection pump and there's NO fuel coming out at the lines going into the injectors. I removed the inlet hose at the pump and TONS of fuel streams out. I read a clogged return line {usually the 'elastacast' ring disintegrating and causing the clog} will stop these pumps and was very hopeful this was my problem. I turned the motor over with the return line disconnected & routed into a catch-can but still NO FUEL going to the injectors. Anyone experienced this or know what I might try next? If I have to I'll send it to a pump shop, but if it's something I can diagnose and / or fix myself that would of course be my preference.

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(quoted from post at 14:40:10 05/18/15) EXACTLY. Simply disconnecting the return line from the fitting/check valve doesn't prove a thing.

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(quoted from post at 15:34:32 05/18/15) That sounds to me a worn rotor. I would take the timing cover of the pump and look if the timing mark turns around when you turn the engine over.
If it doesn't then the pump drive shaft is broken,.usually because the rotor seized in the head. A worn rotor and bore are often scored, a drop of water in there causes rust after sitting a couple months he rotor is seized and the next start might just break the shaft.

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(quoted from post at 00:53:05 05/20/15) Delivery valve stuck maybe?(you need to take the top of the pump off to check that).
Other possibility is that the barrel screen on the fuel supply line fitting at the pump is clogged.
thirdly, if you have an electric shut off solenoid on the pump maybe it ain't getting power when you turn the key on.
fourth, make sure the return line to the tank is open.

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(quoted from post at 06:02:49 05/21/15)

(quoted from post at 00:53:05 05/20/15) Delivery valve stuck maybe?(you need to take the top of the pump off to check that).
Other possibility is that the barrel screen on the fuel supply line fitting at the pump is clogged.
thirdly, if you have an electric shut off solenoid on the pump maybe it ain't getting power when you turn the key on.
fourth, make sure the return line to the tank is open.

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Bison, thanks so much for your help! I'll read up on the delivery valve, but I might be getting to the point where I should just take it to a shop if taking the top off is very involved or anything could pop-out or come apart as I remove it, causing further problems. I can check the fitting on the delivery side pretty easily though, and will do that. This is a manual shut off, where pushing the throttle all the way past slow cuts off the fuel and shuts the motor down. I'd say the return line is open since I took the return line fitting off at the pump and no fuel came out when I turned the motor over.

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