Hi people. I have the above mentioned machine for many years now. It's a 1975 unit. The machine will start and run great for about 5 minutes then will slowly start to lose power so it seems like it's running on only 1 cylinder. I have changed fuel filters,cleaned the fuel tank,and observed the return line pumping fuel back to the tank. I also cleaned the filter in the CAV injection pump. New fuel doesn't make any difference. I'm a decent self taught mechanic on my machines as I have a dozer,excavator,payloader and Massey ferg tractor which I fix and maintain when needed. This ones driving me bats. You might say it's a bad injector pump except that it runs great for the first five minutes so I am tending to rule that out. Anybody have any thoughts to help me out would be greatly appreciated. Thanks,Dan
When it is running at it's absolute worse, slowly loosen the fuel tank filler cap and listen for a hissing sound. If the vent in the cap is plugged there will be a vacuum in the tank.
When did the problem start? and how did it progress? You could try a piece of clear tubing in the fuel return to see if there's bubbles, or if the flow drops when the engine starts dying. Is this a mechanical pull shut off, or electrical shut off?
It's a mechanical shut off. I'll try that today if the rain ever stops in upstate NY.
The filter oring.?? has to go UP IN the filter head NOT ON the filter.. You end up sucking the filter dry & it shutting off.. let it sit & it slowly fills the filter & again, runs till the filter drains.. Its a vicious cycle.. lol Whay about a supply pump.?? or is it gravity feed.?? Have u pull the line off at the inj. pump INLET & hold it over a 5 gal bucket & WATCHED the flow.. ya gotta watch it for any slow down for like 5 MINUTES.. fill that bucket 1/2 way.. your looking for any debris in the tank that might be covering the outlet pipe in the tank.. Go to a Ford NH website & see if u can find a breakdown of the fuel tank.. A LOT of'm had filter screens on the outlet tap.. could be clogged.. HOW was the filter inside the pump inlet.?? THAT right there, will tell u the conditions your working with..
Have you cleaned or changed the screen ? #9 in the image. It is part of the petcock assembly on the bottom of the fuel tank.
I think I have installed the filter ORING correctly but I will check it again. Hte screwing with the fuel. If not done correctly,priming the system again is a nightmare.I don't get why Ford didn't put a primer pump on the inj. pump. Any way,I could probably use the INJ. pump supply line into a clean can of diesel and bypass the filter. The only problem I see is that there are 3 filter lines,1 supply and 2 going to the Inj. pump. Which one feeds the pump? What is the other ,a bypass,return ? Here's a pic. Also it is a gravity feed. I have cleaned out the tank and its petcock filter. Also the Inj. pump filter. You may have a point about the O ring though. I notice that when it starts running lousy and dies,I wait 5 minutes and start it,It will run good for about 30 seconds and dies again.I wish HE Forums would install a voice chat option. So much easier. Dan
I just cleaned it. Its in great shape now. Not the problem
Good flow of fuel to the filter when it was removed ? Still a good flow out of the filter and at the inj. pump ?
100 bucks says its the oring.. those napa filters are known for it.. U GOTTA physically put it UP IN the filter head & MAKE SURE it doesnt fall when your assembling the rest..
Would anyone have an electrical schematic for this machine. I want to get all of the gauges and warning lights working again while trying to figure out the power loss problem too.
I can't say how many times I checked those filters that they changed and called and said it won't run. Pull the filter and the small oring is in the top of the filter and has the passages sealed shut.
I have pulled my hair out over those filters but they normally are not a problem. Man called me to look at Ford backhoe he dragged home for $700. It had the center of a previous filter stuck up in the the housing with the new filter on top of it. Still runs good. Laughed under my breath at the guys working on a farm tracker that would not start. Very similar to yours. One of them turned the water hose on the pump for a few minutes. It fired right up and ran. Said " Yep bad pump ". It was fine after the pump was replaced. Best not to laugh. Sometimes you might learn something.
Just for everyones info.. u know the tid-bit that u put away for a rainy day.. When the water hose was ran on the pump.. & Im not saying to do that as a diagnostic tool by no means.. They shrunk the metals in the delicate Head & rotor, & it tightened up enough to pump fuel... It was actually leaking internally & not pumping the fuel to the injectors.. MOST folks wouldnt do THAT.. they would simply pull the pump & let experienced eyes take a look.. & while were on the subject of water hoses & inj. pumps.. NEVER, NEVER spray a pump down while the engine is running.!! For the exact same reasons as above.. The cold water hits that pump & immediatly locks up the head & rotor.. U can put THAT INFORMATION to the FRONT of your brain.. EVERYBODY NEEDS to know THAT..
Hey Pump Guy, I disassembled the filter. There are 4 O rings. 1 for the bottom of the filter can,1 for the top of the filter can,1 tiny O ring that fits on the securing bolt and 1 on the top of the filter itself. I assume that one comes attached to the filter. How does the tiny O ring get installed? As far as I can see,it only rides as far as the top of the threads. Should I push that one all the way to the top of the bolt tube or let it sit on top of the threads, What is it's purpose? Her are some pics.Thanks Dan
The problem is starring u in the face.. the oring is ON THE FILTER!! Not up in the housing Remove that oring in #4 picture.. U see the slots under it.?? That’s were your fuel should be coming from.. & it’s blocked by the oring... Get it NOW.?
Got it big time. Was looking at the filter trying to figure out how it filtered with no inlet side to it. Thought that O ring came that way on the filter right out of the box. Now I see that that O ring was blocking the inflow. What a stupid design. I will install it tomorrow the correct way and get back to you. Thanks Dan
I have to disagree.. if u bought the factory filter, it’s not like that filter design.. & just to drive it home.. u were told by SEVERAL people what the problem was.. I’m glad u finally understand.. Happy Tractoring..
There are 3 O rings with this filter. You guys kept mentioning the small O ring. Check picture #1. To me that is the small O ring being that the other 2 are 100 times larger. There was the confusion I was experiencing.What exactly does that small O ring do anyway?
I'm sure when I put this back together in a few minutes from now,this machine will run like a champ. Dan
Picture #2 shows where the o rings go. the one on the bolt seals the bolt head. The small one inside the filter head seals the filter to the head to prevent unfiltered fuel bypassing the filter.
I fixed the O ring problem and it ran great. I took it for a ride around my 100 acres. Ran really strong then started to lose power and finally stall. Let it sit 2 minutes and restarted. Ran normal again,went 200 ft in 1st gear and started losing power again. Let it sit and restarted and so on and so forth. Doing that I was able to get it back to the barn. Seems to run great at full idle when not in gear and under load.. Feels like it's starving for fuel. I know I washed out the fuel tank and blew the lines last year. I'm going to pull the filter again and see if that gasket slipped down onto the filter top. Don't see how that could happen as it's sandwiched in.Only other thing is to drain the fuel tank and check the petcock filter again. P.S. look at this pic. Are the filter housing lines hooked up to the correct ports? Seems to me that the back right one should be on the front right port.Don't remember ever moving them.
If you didn't mess with those lines before, then don't mess with them now. If the filter o ring was put in the housing, and then it worked, don't mess with that filter again, yet. Take the line from the tank off? will that run full for a full minute? if not, pull the shut off valve and clean that screen again. Do you have a drain on the bottom of one of the filters? drain that into your hand or a jar and see if there's any water or sediment. Any old rubber lines? replace them.
I HATE that filter set-up.. U see the rubber line connected to the the steel line,?? Thats the fuel return from the pump but the arrow is pointing OUT.?? 1 other thing.. U ever heard of BRAKE KLEEN.?? Its a wonderful product for cleaning grease, grim & oil off of MANY DIFFERENT THINGS.. Lol The problem your describing is a classic case of starving for fuel.. just like the filter is dry then refilling slowly.. like an oring is out of place.. or theres a vacuum problem.. BEFORE u try the outlet tap screen, try running it w/ the fuel cap OFF.. & dont try trouble shooting it w/ 5 gallons of fuel..
Also be sure the return line to the tank is clear-open.
I've been looking at that rubber return line going to the out arrow port for a while now,just like your question marks on the subject. The two out arrows are the same chamber after the filtered fuel. Possibly it's intent is to push return fuel out through the the other out arrow. I can't find any answers to that question. I switched the line to the in arrow. Now I have to reprime the system which is of course a nightmare. I'll try running it like that and see what happens before I investigate the fuel tank screen because last fall I completely drained and washed it out and cleaned the petcock filter so I'm leaning towards a different solution. I was a heavy construction electrical foreman for most of my 38 year career so I am quite experienced in logical troubleshooting. Never had a problem that wasn't solvable. I'll keep you guys in the loop. Dan
AS TENWHEELER ASK IS THE RETURN LINE OPEN TO THE FUEL TANK?
The return line runs from the inj. pump to the top of each fuel injector then to what looks like a diaphragm and then to a small pipe which empties into the fuel tank just below the fuel tank cap. It flows but how much is it supposed to flow I don't know.It'snot a hard stream but it flows and drips into the tank.
check the lines for being full open!! rubber lines bad to get pinched partially close
Hi Guys,been busy. I Checked the filter gasket again,still intact and correctly positioned. Disassembled the return line at the tank and blew it back to the filter with the filter off. Blew out easily so not blocked. Reassembled and bled out and restarted and seems to be running normally with full power. All that's left is to take it on a half mile ride up and down hills and see if the problem disappeared. Wish me luck. I'll let you know what happens. Thanks again for your advice. Dan
Okay,I was using the backhoe making a trench. Was running great for about 15 minutes then started losing rpms and power. Finally stalled. Waited 5 minutes,started and ran great again. Then lost power. Must not be getting enough fuel to fill the filter but I've done everything I can do. Wish I had a clear filter so I could see if that's the case. Maybe I should rig up a float bowl of some kind so I can watch whats happening. Maybe it has a Diesel flow Virus.
Seems to run fine at idle but as soon as it goes under load and require more fuel is when the problem starts.
It’s the filter under the inlet nut .. it’s clogged.. If all else fails, & it sounds like it has, put an electric pump on it.. No more than 10 psi tho.. How many times are u gonna keep taking the same things apart w the same result.?? Just askin for a friend.. lol
The main filter after the fuel tank inlet or the inlet on the Inj. pump?
If pumpguy's suggestion isn't the problem, remove the the fuel tank filler cap after it the engine slows down or dies. You will be looking for /or if there is a vacuum in the tank. Plugged tank vents are notorious for the symptoms you have.
Probably already covered this, but does it still have the needle valve and glass bowl under the tank? Those were terrible about clogging repeatedly. I take them out and replace it with a 1/4 turn ball valve.
Did that yesterday. No change.
Just has a pet cock valve with a filter in the tank above it. all clean.
Pump guy says. "It’s the filter under the inlet nut .. it’s clogged." But which filter?
Sorry bud.. I got busy.. Theres a plastic filter inside the pump.. U HAVE TO BE CAREFUL.. Pull the 15/16 nut & copper gasket.. Pull the big spring.. & adjuster.. NOW, HOLD THE GUTS DOWN W A SMALL SCREWDRIVER.. & take a 90* scribe & pick up on the filter.. Its on the "outside" of the guts.. I sure hope thats the problem.. Good Luck.
Thanks, did not know that.
Ur not supposed to know THAT.. Its ancient Chinese secret !!!
Got the filter out,easy peasy. Half dirty,has a breach in one part. Ordered a new one,comes in thursday. I'll let you know what happens. Dan
Don’t u know who I am.??!! I’m the guy who gives parts away.. I’ve got a boatload of’m.. Oh well, live and learn..
OK boys. It's been lousy weather here but last Saturday I put in the new filter and took the hoe for a 1 mile ride up and down hills and it didn't even burp. Think the problem is solved thanks to Pump Guys suggestion. My thanks to everyone for their helpful hints and interest with this project.I'm sure we'll talk again as I own many machines. My next project is fixing the brakes on a 1960s Michigan payloader.It's got a vacuum controlled brake canister system. First I have to change the front left wheel cylinder. That should be a challenge.Anybody know how they work or where to get free manuals?