Mccormick b250 won't start

[Mur Huwcun]

When you crack open the pump bleed screw it should come out at a fair rate when it's fully bleed. Sounds to me unfortunately that the pumping elements in your pump are not very well by now. Had this with two pumps wherethe pressure was down. Towing or a whiff would get them started and then run ok.

They're not the best for the first few seconds after starting and on my 275 you need to keep the heater plugs on fir few seconds after the engine gets going. Have you tried easy start again just as it gets going just to give her a chance, use sparingly just as the engine is firing and you may get it running to make sure it's bleed properly

 

[Right-arm fast]

Anybody know as to how much pressure should be in the fuel filtre housing before the overflow valve opens and sends fuel down the injector leak off pipes and back to the fuel tank?

Even when I operate the hand primer fuel rushes out the overflow valve so just wondering if it's going back to tank and not sending enough pressure to the injector pump as when I try to bleed the injectors I only get a dribble and not a good squirt?

Anyone got a video showing how much they should squirt when trying to bleed the injectors?
Thanks

Usually the leak off fuel flows from the injectors in to the lines that feed the pump or go back to tank so at most they only have to overcome lift pump pressure. The fuel filter will have lift pump pressure in it which maybe regulated by the spring in the lift pump.
One thing I find strange is that it did run well but you are having trouble with no4 injector etc. I think you need to check the delivery valve for this pumping element. If this valve is stuck open it will inject very little fuel into the combustion chamber if any. Where the no4 injector line is screwed to the union on the pump you need to undo the union and inside you will see a spring under the spring is a fluted valve which is a precision fit into the top of the barrel with a chamfer to seat. Very carefully lift it out may need a small set of pliers and check its not stuck or sticking. Eliminate this as a cause as it will cause a huge problem if its stuck open - the line pressure will struggle to build high enough to lift the needle in the injector.

 

[Mursal]

 

[REStracTORATION]

Try taking all injector pipes off the pump and crank it over you should see a good positive spit from each
Where abouts are you at??

 

[Bully1]

Try taking all injector pipes off the pump and crank it over you should see a good positive spit from each
Where abouts are you at??

Hatton Derby uk

 

[Bully1]

Try taking all injector pipes off the pump and crank it over you should see a good positive spit from each
Where abouts are you at??

Took pipes of and cranked over it spits about 5mm high out of outlet not much

 

[Mursal]

As you know, be careful with the output from the injector pump, do not put your fingers (skin) near the pipe when its cranking.

 

[Bully1]

This ain't my one but the same, look at the injector leak off/return pipes going back to the tank, there's a pipe coming from the fuel filtre bowl that connects to it which is and over flow valve out of housing but even when hand primer is used the fuel rushs back to tank let alone when cranking the engine,
Could this be letting the pressure go back to the tank rather than putting it into the injector pump which would explain low pressure from injector pipes
When I took it off it had dirt around it and is spring loaded but it was rusted inside so I can't strip and clean it, is this part available to buy?

 

[Mursal]

I would just block it, to test
Get something that will fit into the pipe end like a ball bearing or brass rivet.
Remember the injector pressure (2000psi hence the danger to skin) is created by the element moving up as the pump shaft turns. The lift pump must ensure the space above the element in the pump is full of fuel at low pressure (7-10psi).

 

[John 1594]

Have you checked to make sure the rack is moving in the pump?

yes the elements may go up and down when the engine is cranked, but if the rack is in the stop position, or the spring inside the diaphram has failed, it will not go, simple as that

 

[Bully1]

I would just block it, to test
Get something that will fit into the pipe end like a ball bearing or brass rivet.
Remember the injector pressure (2000psi hence the danger to skin) is created by the element moving up as the pump shaft turns. The lift pump must ensure the space above the element in the pump is full of fuel at low pressure (7-10psi).

I shall try that tommorow

 

[Bully1]

Have you checked to make sure the rack is moving in the pump?

yes the elements may go up and down when the engine is cranked, but if the rack is in the stop position, or the spring inside the diaphram has failed, it will not go, simple as that

I've removed the inspection cover and yes all 4 turn when the stop lever is moved haven't check condition of diaphragm yet tho

 

[Right-arm fast]

Took pipes of and cranked over it spits about 5mm high out of outlet not much

There isn't a lot of pressure needed to lift the delivery valve so it wont spray as if it were coming out of the injector nozzle. It will only be a very small amount of fuel for each delivery too. You have got the injector pipes going to the right injectors from the pump ?

 

[Bully1]

There isn't a lot of pressure needed to lift the delivery valve so it wont spray as if it were coming out of the injector nozzle. It will only be a very small amount of fuel for each delivery too. You have got the injector pipes going to the right injectors from the pump ?

They are formed to each outlet so it would be difficult to get them wrong unless you bend them to shape so yes they should all be on the right connector

 

[John100]

A pump doesn't build pressure if its disconnected from the injectors, not a lot of point testing it like that

 

[Bully1]

Removed the pump outlets and plunger and found some dirt
I worked the hand primer and empty about 1/4 tank a diesel trying to flush it though and got a constant stream of bubbles but hand primer leaking so probably sucking it in through there after putting it all together I bleed the system but every time I crack number 4 after rotation has stop it squirts air out try this about 10 times

I then removed the diaphragm and tried to start it and it fired straight up and ran for aroundv10 seconds before it died I fiddled around with the excess fuel lever in side and it fired and ran for a few seconds then cut out
What are thoughts?
Could it be the diaphragm there no tears but is damp with fuel or oil but only found a smear on the inside where it sits?

 

[Mursal]

I see you have 1 pipe going to the inlet manifold from the pump diaphragm, so its spring pressure keep the revs on the engine and vacuum that cuts the revs back. So unless the rack is stuck towards the clutch pedal (tick over) and is not moving forward towards the radiator (full revs) its not the diaphragm.
It sounds as though its just getting air, the next time it runs, try using the hand primer .........
The bubbles are not good ..........

Edit:
Not sure about No4 injector, but it should start on 3 cylinders, not ideal but it should eventually

 

[Mur Huwcun]

Where have you got the throttle set when trying to start it? Too much and they won't go!! I find that the excess makes things worst aswell. Set the throttle just above idle and try again. Leave the no4 injector pipe loose at injector to bleed through. It will run on three, mine did for about three minutes when the plungers were stuck and I just pushed them back down every time as it ran!!

 

[Bully1]

I see you have 1 pipe going to the inlet manifold from the pump diaphragm, so its spring pressure keep the revs on the engine and vacuum that cuts the revs back. So unless the rack is stuck towards the clutch pedal (tick over) and is not moving forward towards the radiator (full revs) its not the diaphragm.
It sounds as though its just getting air, the next time it runs, try using the hand primer .........
The bubbles are not good ..........

Edit:
Not sure about No4 injector, but it should start on 3 cylinders, not ideal but it should eventually

Going to have to buy a new hand primer I think but won't start on 3

 

[Bully1]

Where have you got the throttle set when trying to start it? Too much and they won't go!! I find that the excess makes things worst aswell. Set the throttle just above idle and try again. Leave the no4 injector pipe loose at injector to bleed through. It will run on three, mine did for about three minutes when the plungers were stuck and I just pushed them back down every time as it ran!!

Tried in all position seems to fire better if near fully open but before it packed up I only moved it slightly from closed and it fired up fine won't fire up on 3 either it may still be getting some air to other injectors but number 4 is the only one squirting air out