7040 low power issue

Hello all, new to the forum so please don’t laugh at me to much. So I have a 1976 7040 that I got from my father-in-law , the tractor has been repowered with a N6 combine motor long ago (1983 model I believe), it hasn’t ran in probably 5 years , I dug it out of its grave pulled the pump and injectors out and sent them off to a guy to have them gone threw , this tractor has the roosa master db2 pump I believe and Bosch injectors. Tractor in it’s day was around 250hp and I do remember it being very powerful and would hang with our newholland 8770 genisis   So to current time I have it running and have put several hours on it and it runs well and runs smooth but is very lack for power I’m thinking maybe around 90-100hp tops   Struggles to run a 15ft batwing in short grass , our other 7040 that is completely stock runs circles around it . I have redone the fuel system to a spin on filter and also has a small electric lift pump , checked and checked again and always have gobs of fuel to the pump , have messed with the timing gear and have it to where I believe it should be , tractor starts pretty well and does smoke and is responsive down lower in the rpm’s but as it gets higher like 1600+ it becomes less and less responsive and very laggy but continues to smoke like a train   And will work for you but just is nothing like it use to be .I’ve asked a lot of people about it and tried many of things but it has me at a total loss. Seems like the pump is just turned way down but from my understanding it can’t be turned up unless on a stand , I have the “torque” screw about all the way out and made no difference in power . I am no mechanic when it comes to injection pumps , Any help would be appreciated , thanks all

I will double check them tomorrow morning when I get to the farm I didn’t think I could put them in backward cause I thought they had a groove in the head and a little tit on the Injectors but now you got me questioning myself . I haven’t reached out to the guy that went threw them for me , he’s not a allis guy but was nice enough to work on this stuff for me and I hate to complain about something not knowing if it even has anything to do with pump or injectors

AC injectors cannot be put in wrong, inlet on side prevents that error. Bosch injectors have no locating ball or notch to ensure they are properly installed in the head. One just needs to know the return bolt goes to the valve cover. I guarantee it'll run better with them installed the right way. I've seen this happen with IH and JI Case engines as well. It happens.

Just a thought,you might check your air filter system to be sure
no unwanted critters have the filter home and restricting air flow.

Do us all a favor and install a no more than 30 PSI gauge in the intake manifold and tell us how much turbo boost pressure it makes with the throttle WIDE OPEN and pulling hard down to 2300 RPM's. I got news for you....it NEVER had 250 HP.

Edited by DrAllis - 11 Jun 2023 at 6:34pm

I do remember when I was dating my wife probably 11-12 years ago now when he still farmed with some I pulled a 40ft Phillips harrow with it same one we usually pulled with the 7580

Pulled the Injectors, turned them around and stuck them back in today and she runs great! Haven’t worked it yet or got a boost guage on it but will try to tomorrow but acts 100% better. Thanks injectionpumpEd and everyone else that commented so far

Be careful there, I think combine engines were rated at flywheel hp so not a true comparison.

I think your pump needs put back on the test stand and corrected. No boost,no power. It's not delivering enough fuel.

Edited by SteveM C/IL - 14 Jun 2023 at 10:10am

You're probably right in thinking it's a fuel flow to the pump restriction. Happens all the time, people think they have injection pump issues, when it's a plumbing issue. 

I’m reading that you want to competition pull with it too? ….and brush hog.

Tomato tomato….ok, but pulling. Call it what you want

Injpumped is there a way I can talk to you on the phone?

Hardly any smoke out the stack at all   It does have some blow by. She is tired and I know it , but she isn’t shot . I think it’s in the pump somewhere checked the timing again and retimed it to dead on 18* pulled fuel lines and inspected. Took off lift pump and would not start without it , put it back on and rebled it and got it running messed with timing advance on pump after talking to pump guy and it’s almost all the way in and has a decent ping to it now so guessing it’s advanced pretty good, was the only way to make it not pop as it revs up but still a complete t**d and no smoke