v23nb
New member
I have just resolved my starting problem as a direct result of advice received from here. My solution brought up some things I haven't seen here before so I thought I'd write them up in case they may be of help to anyone else.
I bought my 1971 3000 diesel last summer. Generally it is in good condition however it didn't quite rev to the full figure which I partly put down to interference from the foot throttle which was caked in aftermarket blue paint. It still had plenty enough pull for what I need so didn't worry too much about it. Then a couple of months ago it was running at a fast idle while I changed implements on the 3 point hitch when it just petered out. After a minute or two I could restart it but it would only run for about 10 seconds as long as I held the throttle wide open while never getting higher than about half revs. I changed the fuel filter which was pretty cruddy so I decided to drain and flush the tank at the same time. I replaced the gauze filter in the tap while I was at it. After bleeding the system the engine behaved exactly the same way with the 10 second run (after a helluva lot of cranking) before fading. I then pulled the injectors and gave them a good clean. Before you couldn't even make out the holes and they were more of a single jet out of one single point whereas after cleaning they were operating a proper spray pattern from multiple orifices. Surely now she would run but no, it faded just the same but after a 20 second run this time. I came to the conclusion that it was the dreaded CAV DPA injection pump. I gulped when I read the exchange price is about US$700 so started looking into the option of doing a DIY overhaul. All the info here said it was not an amateur job but having downloaded a couple of manual for the pump online I ordered an overhaul kit from a bloke here in the UK for £20. When it arrived it turned out to be a phenomenally comprehensive kit with more than I needed as it was good for pumps supplying 6 cylinders.
I'll start a new paragraph here as the following is info that I deduced myself that is the key stuff that might help others. Firstly, this is not quite the nightmare the other people suggested. I am not a mechanic, I am an airline pilot, so while I am reasonably sensible I am no expert. If I can do it, so can you.
Disconnect the battery. The workshop manual doesn't say to do this to remove the pump but you are working very close to the terminals on the starter motor and a spanner will connect at some point! You will also need to drain the radiator as one of the hoses covers the plate that allows access to disconnect the pump from its drive. Catch the fluid as I was horrified that it cost me £30 in new antifreeze after having let perfectly good stuff fall onto the ground! The system takes 13 liters in total. When you eventually disconnect the pump and lift it out the gear wheel that it attaches to is held tight enough by its casing that it can't jump a cog from the bigger drive gear wheel. I had been concerned that the loose assembly might allow it to jump a tooth and mess up the timing. This isn't so and also the drive gear has a pin on it that slots into a groove on the pump so you cannot reconnect the pump with it out of alignment. That is the static timing catered for but before removing the pump clean back the dirt near the closest fixing bolt and take a note of the notch position against the dynamic timing marks. Mine was still in the middle position so that is what I reset it too on reassembly and it worked fine straight away.
Having got the pump off I then worked on it on a bench. I had expected the pump was full of fuel but (obviously, I guess) the internal space above the bleed screw is actually full of air. The top cover contains all the control mechanism and this is the bit as others have described that needs special care when disassembling. The downloadable manuals for the pump cover this area quite well so I won't cover unneccessary ground.
The reason I wanted to write this post is because my problem is probably very common and I suspect people are spending a lot on exchange units when they don't even need to remove the pump! It turns out I could have left my pump in place too! On the rear of the pump there is a fuel line that comes from the filter into the rear from above. Where this line enters is called the end plate. Take it off by undoing the fastening screws and inside you will find another filter in the end plate that no one told you about! This was completely clogged in my pump. Clean it out and reassemble. While you are at it there is another item on the underside of the pump held on by 2 different size bolts. This is the automatic ****** device for starting. If the filter was clogged then this item at the lowest point will also be clogged with sediment so clean it up. As I said earlier, these items can be done in situ and if the problem is a fuel starvation issue then this may well fix it without even having to undo the more complex control assembly at the top of the unit.
Thanks to all who gave me the encouragement to have a go. You saved me hundreds of pounds and I have learned a lot about my tractor and myself along the way. If just one person benefits from reading this then it was worth my time writing it.
I bought my 1971 3000 diesel last summer. Generally it is in good condition however it didn't quite rev to the full figure which I partly put down to interference from the foot throttle which was caked in aftermarket blue paint. It still had plenty enough pull for what I need so didn't worry too much about it. Then a couple of months ago it was running at a fast idle while I changed implements on the 3 point hitch when it just petered out. After a minute or two I could restart it but it would only run for about 10 seconds as long as I held the throttle wide open while never getting higher than about half revs. I changed the fuel filter which was pretty cruddy so I decided to drain and flush the tank at the same time. I replaced the gauze filter in the tap while I was at it. After bleeding the system the engine behaved exactly the same way with the 10 second run (after a helluva lot of cranking) before fading. I then pulled the injectors and gave them a good clean. Before you couldn't even make out the holes and they were more of a single jet out of one single point whereas after cleaning they were operating a proper spray pattern from multiple orifices. Surely now she would run but no, it faded just the same but after a 20 second run this time. I came to the conclusion that it was the dreaded CAV DPA injection pump. I gulped when I read the exchange price is about US$700 so started looking into the option of doing a DIY overhaul. All the info here said it was not an amateur job but having downloaded a couple of manual for the pump online I ordered an overhaul kit from a bloke here in the UK for £20. When it arrived it turned out to be a phenomenally comprehensive kit with more than I needed as it was good for pumps supplying 6 cylinders.
I'll start a new paragraph here as the following is info that I deduced myself that is the key stuff that might help others. Firstly, this is not quite the nightmare the other people suggested. I am not a mechanic, I am an airline pilot, so while I am reasonably sensible I am no expert. If I can do it, so can you.
Disconnect the battery. The workshop manual doesn't say to do this to remove the pump but you are working very close to the terminals on the starter motor and a spanner will connect at some point! You will also need to drain the radiator as one of the hoses covers the plate that allows access to disconnect the pump from its drive. Catch the fluid as I was horrified that it cost me £30 in new antifreeze after having let perfectly good stuff fall onto the ground! The system takes 13 liters in total. When you eventually disconnect the pump and lift it out the gear wheel that it attaches to is held tight enough by its casing that it can't jump a cog from the bigger drive gear wheel. I had been concerned that the loose assembly might allow it to jump a tooth and mess up the timing. This isn't so and also the drive gear has a pin on it that slots into a groove on the pump so you cannot reconnect the pump with it out of alignment. That is the static timing catered for but before removing the pump clean back the dirt near the closest fixing bolt and take a note of the notch position against the dynamic timing marks. Mine was still in the middle position so that is what I reset it too on reassembly and it worked fine straight away.
Having got the pump off I then worked on it on a bench. I had expected the pump was full of fuel but (obviously, I guess) the internal space above the bleed screw is actually full of air. The top cover contains all the control mechanism and this is the bit as others have described that needs special care when disassembling. The downloadable manuals for the pump cover this area quite well so I won't cover unneccessary ground.
The reason I wanted to write this post is because my problem is probably very common and I suspect people are spending a lot on exchange units when they don't even need to remove the pump! It turns out I could have left my pump in place too! On the rear of the pump there is a fuel line that comes from the filter into the rear from above. Where this line enters is called the end plate. Take it off by undoing the fastening screws and inside you will find another filter in the end plate that no one told you about! This was completely clogged in my pump. Clean it out and reassemble. While you are at it there is another item on the underside of the pump held on by 2 different size bolts. This is the automatic ****** device for starting. If the filter was clogged then this item at the lowest point will also be clogged with sediment so clean it up. As I said earlier, these items can be done in situ and if the problem is a fuel starvation issue then this may well fix it without even having to undo the more complex control assembly at the top of the unit.
Thanks to all who gave me the encouragement to have a go. You saved me hundreds of pounds and I have learned a lot about my tractor and myself along the way. If just one person benefits from reading this then it was worth my time writing it.
I'm itching to get to work on this thing.