Trying to fix my great uncles Mitsubishi MS 240-8

[WRA]

Long time lurker and first time poster here.

We have an 84 Mitsubishi MS 240-8 excavator on our farm and it hasn't run in a few years, but there have been a few things that need to be done on the farm (dam repairs, stump removal, removing several beaver dams...etc) that would be much easier to do with the machine running.
I am trying to troubleshoot it based on what I do know from what my family has told me.
I have never run an excavator before, so I am not going to pretend to know much about them. However I would like to get the chance to do so.


So here is what I know...
To get the machine to start they told me that they have to manually inject fuel into the engine to crank it.
Apparently they are able to get the machine to start and it will run for just a few seconds and then it will quit.
They drained the fuel, and refueled it.
They seem to think that it has to do with a missing fuel cap and something about the fuel being gravity fed, so they ordered a fuel cap, and proceeded to forget to pick it up at the dealer that they ordered from.
The relatives that I am trying to help are about six decades older than I am, so they can only do so much nowadays.

Does anyone have any ideas as to what could be going on?
Many thanks!

Wes

 

[Delmer]

They probably meant that you have to prime the engine to get it to start? maybe? Or did they mean you have to spray starting fluid into it and then it will run a few seconds and die? There's a huge difference between those two regarding how likely you are to be able to start this. Please clarify which of the above is the case.

I kind of doubt that the fuel is gravity fed. The missing cap could be the biggest cause of the problems, but a new cap won't make it start. Do you at least have a tin can taped over the fuel opening now?

I'd go through the whole fuel system from tank to injection pump and back, blow it clean or brush it clean, look at every rubber hose for cracks or leaks, every steel line for kinks or leaks, pay attention to any area that had an unusual buildup of dirt. Note the water separator (might look like a filter base with two plastic cylinders threaded in), but don't unscrew the bowls unless you see water in them. If the bigger line from the tank goes to a part attached to the injection pump and then to another filter, and back to the injection pump body, then that first part is the transfer pump and probably has a priming pump on it, unscrew the one inch diameter knurled round knob and pump it to prime. Open the bleeder on the fuel filter and keep pumping until you get fuel, then take the banjo bolt out of the bottom of the transfer pump and check if there's a plastic screen screwed inside of it, remove, clean, replace and see if the flow out the filter increases. Then open the bleeder on the injection pump body till you get fuel.

GOOD LUCK

How about a picture of the injection pump for starters, and pics of any part of the fuel system that you're not sure what it is. I guess a lot better with pics.

 

[Delmer]

Does the injection pump look like this one?

https://www.heavyequipmentforums.com/showthread.php?58560-Help-please-Excavator-fuel-issues

Only six injection lines maybe. The round thingy at the bottom of the picture is the priming pump knob, and the banjo bolt you want is underneath, pointing UP into the bottom of that pump.

Here's a thread with a picture of a banjo bolt and screen inside it.

https://www.heavyequipmentforums.com/showthread.php?20891-Fuel-line-banjo-bolt-screen-problem

 

[WRA]

Delmer; Thanks for the info, I will see if I can get any pics of it soon. The machine is about an hour and a half from me at the moment, so I will get some at the next opportunity.

 

[WRA]

Service Manual

I am also in the market for any service manuals for this excavator if anyone has one.

 

[thepumpguysc]

Yup, Delmers got you covered on this one..
it should have a hand primer pump bolted to the side of the injection pump IF its an inline pump like the one pictured.. read about the "banjo bolt"..
IF its a rotary pump, where the lines come off the pump, in a circle.. there should be a remote HP somewhere in the system..
A lot of times its just a rubber pump bulb, like the ones found on a boat gas tank. OR and electric pump somewhere in the feed system.