Check the fuel return to be sure it is open. If it is stopped up, the engine will only run till pressure builds in the return and then quit. It return is ok, I would run a test line from the fuel pump suction line back into the fuel tank and try it . You could have a fuel suction issue. If both of those things check ok, I would try cleaning the injection pump. Just don't break anything, at this point , you don't have anything to lose. Let me know. Thank you.
Curtis - I have since learned that the button activated by an external solenoid next to the injection pump is an excess fuel solenoid. Hard to find diagrams that explain most of those things. Sometimes I feel a bit like Sherlock Holmes. I will check the fuel return. Makes sense. On this machine, it appears to be a vapor return...banjo fitting connected by a banjo bolt to the front injector...connects to a line that returns to the tank. I misplaced the banjo bolt while I was rebuilding and had to order a new one. I guess the best way to try may be to just disconnect that bolt and try to get it to run. I'll also blow out the line. That's the one line I didn't replace. I may have junk in things only because I chose to used compressed air to force fuel back into the system after I put it back together. On the test line part, I assume the following: On 731 fuel goes from tank to engine mounted mechanical fuel pump, then to filter, then to mechanical injection pump. I will run line from suction side of fuel pump to tank, prime and check. Same might work for injection pump. I'll try. I'll get back with you. Have to go to funeral today, will try to wedge in spare time. Sincerely, John
Let me know how it works out.
What a sage you are. The vapor return worked fine. I hooked up the fuel supply directly to the injection pump and it worked fine. I then moved hoses around and isolated the filter and then the mechanical fuel pump. The mechanical fuel pump is the restriction. I rebuilt it last week, but that's just gaskets and strainer, etc. I suspect the pump rod or something has failed. I never really was able to get a good squirt out of it. But that's sure a lot cheaper than buying an injection pump. I should have thought to isolate individual components and remember always to check the simplest thing first. I really appreciate your help.