Help! I ran this machine out of fuel a couple months ago. Fueled it up, primed it, and it was running weak, slow to throttle up and would bog down like starving for fuel. Previously it ran great. Now I Had to prime it each time I started it. Eventually it got worse, sounded like it was missing sometimes and it got hard to shut off, would sputter for a bit instead of just shutting off. So I parked it, checked the tank for blockages, garbage, etc. Cleaned out the lines, changed the filter, replaced the primer pump. At this point I am 100% confident the injection pump is getting what it needs from the gravity fuel system. I have bled the injector lines over a dozen times. It currently won’t fire up for more than a moment when I prime it. I got it to run a little longer using the hand priming pump to keep it running. Its just not getting more fuel than it takes to make a little smoke like this:

imgur.com/a/V7ZsmJM

Here is what the spray from the top of the pump looks like:

imgur.com/a/Av3Nt5O

Tonight I unhooked the fuel line at the filter and confirmed strong gravity feed of fuel from the tank, letting it run into a can for awhile.

I hooked up an electric fuel pump and a fuel line feeding from a can and connected it to the inlet of the fuel filter. Still wouldnt start and bled the injector lines again for good measure. The electric pump pushed enough that I could prime pump and bleed injector lines.

 

Bypassed the filter and fed fuel directly into the pump. Same deal. The fuel flows really nicely  out of the injection pump bleeder line when the pump is running and it is directlyconnected like this. It popped and tried to start but still wont fire up. Lots of white then dark smoke. Bled the injector lines again. Ran it on ether a little for the heck of it. I did notice the fuel pressure gauge had movement and it got to half way on thegauge after awhile of continuous cranking.

 

So I pulled the cover off the side of the pump. Not much crud in there. A small bit of shiny particles and some surface rust particles laying on the bottom. The insideface of the cover plate had light surface rust.

 

One thing I noticed is nothing moves with the throttle lever. No rack sliding or anything. Is that something that only moves when theengine is turning?

Checked fuel flow into the pump with the cover off:

imgur.com/a/fhJ4Tx9

I guess next step is remove the injectors and crank it to see what their flow looks like with them hooked to the lines, or something else? Should I just take the injectors somewhere to have them tested/inspected?

I dont think I can really test the transfer pump which is on the front of the pump any way other than cranking it with that side plate off and observing the flow, which doesnt quantify much.

I would look into the governor and throttle linkage. There should be some movement of the rack when throttle is moved. Check that the sleeves in the pump are free.
 I doubt the problem is with the injectors. Just sounds like the governor is not turning the pump on. Good luck 

First things first, you need to develop decent fuel pressure. Maximum fuel pressure is 30 +/- 5psi. You should get at least half of that cranking.
I am bothered by the sight of fuel coming out of the check valve (next to relief valve). That check valve is there to assure priming pump flow is into the injection pump housing. If it fails you have a circulating loop through the transfer pump and will never make other than flow resistance pressure.
There is no rack, you should see rotation of the shaft that controls the metering sleeves. Make sure the sleeves are not stuck.

Edit.....
Cancel the check valve concerns, that only applies to earlier models that had the fuel filter and priming pump mounted to the injection pump cover. In later systems where the filter and priming pump are remote mounted it relies on working check valves in the priming pump. Still the fuel pressure needs to be acquired.
 

Couple more items to check....There is a constant bleed valve in that elbow coming off the injection pump cover plate. Check to see that it is functioning and the spring is intact.
The other item is bleeding the injection pump housing.
See attachments...
 
 

I never knew about the bleeder for the governor housing. I would love to find out all my problems are because I never bled that. I will fill everything back up tonight and bleed that and try to start it.

In my post, in the third picture, I'm pretty sure the constant bleed valve is what I have in my hand, and it looks to be in good condition.

The valve you are referring to in the third picture is the pressure regulating valve, not the constant bleed valve.
The constant bleed valve is in the elbow that comes off the upper LH corner of the injection pump cover plate and is in the line that returns fuel to the fuel tank. It is a combined pressure relief and orifice valve that normally would continuously bleed any air from the injection pump plus assures adequate circulation for cooling. The bleed rate for the fuel is approximately 9 gallons per hour.

This pump arrangement doesn't have a return to the tank as far as I can tell. It circulates fuel around inside the pump housing instead of returning it to the tank from what I understand.

The line on the upper left hand of the pump cover plate is going to the fuel pressure gauge on the dash. I will triple check this in case I missed something.

The line on the upper left part of the governor housing is connected to the air intake.

I've looked high and low for a return line to the tank and haven't seen one yet. My parts book seems to back this up (4N1834 pump arrangement and 6N728 valves and lines arrangement).

OK, some have the return line and constant bleed valve and some don't. Can't tell from here without actually seeing it.
Without the constant bleed it is even more important to get all the air out of the injection pump and governor.
What were your findings on movement of the sleeve metering shaft and sleeves?

Check the fuel supply line or the fuel filter head for blockage since it ran out of fuel. Most of the time, trash will be pulled into one of them. Wouldn't hurt to blow compressed air back into the tank from the fuel filter housing.

Looks like the injection pump is starving for fuel the way it's pumping in your video.

So with the side cover off the IP, and the throttle held to full throttle, the 4 injection pumps are shooting fuel out their dump holes at the bottom of the sleeves. The way I read it should function, the sleeves should be covering these holes when the throttle position is cranked up like I was holding it