fuel system woes

[Phoenix of Hamble]

Rack can be moved with fingers, do not force with tools. essential it is free to move, as if it sticks in the full on position, stop lever might not be able to shut down engine.

Will it move its full travel while the pump is still attached to the engine?... or just move to take up any slack in the system?... i'm just trying to understand how I can ascertain if its freed up.

In addition I ask, as I had also thought about the fact that the engine will effectively be uncontrollable if its stuck, as you say, in the full position, and will presumably only be stoppable by starving the air or fuel supply, neither of which would be ideal!!!!

In answer to other observations, its a isolated oil system, not from an engine feed, so that needs checking too... and the only two bleed screws are on the front as far as I can see.... only other fixings are the oil drain, fill and level check, besides the obvious mounting bolts.

 

[DownWest]

Recently had something similar with a Coventry 2T supercharged Diesel. Except that corrosion had stuck two of the four jerk pumps, so the rack was jambed too. Have to admit that a little force was applied to the rack as the unit was from the 50s an would be a real pig to find parts for. The rough cure worked, as with the side plate off we could see the pumps starting to move ( as in rotate, to vary the amount injected) Knowing the close tolerences of diesel pumps, I was a bit concerned about the results from the stickiness. But, runs fine.

 

[Phoenix of Hamble]

This forum is truly brilliant... it would be properly difficult to get this kind of advice and support anywhere else!

 

[Phoenix of Hamble]

So, looking at exploded diagrams... its the throttle cable that moves the rack and thus rotates the individual pumps and controls fuelling levels?

If so, I assume that by opening the inspection cover on the side and operating the throttle, I will be able to see if the rack is moving correctly?

 

[essexboy]

While you are trying to start the engine can I suggest you make sure that if if it does start you have a way of stopping it ! The blade spring on the govenor can crack if corroded and the engine can run away, needing a swift blocking of the air supply ! Now how do I know that ?

 

[DownWest]

Not quite, the throttle controls the govenor, which then controls the rack. Essentially, the pump supplies lots of fuel to start, then, as the revs come up, the govenor controls the revs to the setting of the throttle. So there is not a direct connection between the the throttle and the rack.

 

[Phoenix of Hamble]

Ok, that makes sense... but, i'm still not clear on one thing... can I move the rack through the inspection port (assuming its not jammed), or will the govenor prevent it moving to any great degree?

 

[david_bagshaw]

rack will move the same with the pump on or off the engine.

however if the stop lever is in the stop position the rack will be held in the no fuel position , and thus cant move. There is no connection to the control of fueling and the engine. it is all done by the governor and linkage, which is in the pump casing.

Emergency shut down is easily achieved by slackening the pipes to the injectors.

 

[Phoenix of Hamble]

rack will move the same with the pump on or off the engine.

however if the stop lever is in the stop position the rack will be held in the no fuel position , and thus cant move. There is no connection to the control of fueling and the engine. it is all done by the governor and linkage, which is in the pump casing.

Emergency shut down is easily achieved by slackening the pipes to the injectors.

Thanks David... that's just what I wanted to know... so I can now try and free the rack in position, knowing that if it won't move i've identified the problem.

I took the filters off the engine to get at the starter motor to replace it, and discovered that the foam elements had crumbled, so currently, the easiest way to stop the engine in the event of a run away or lack of governing is simply to slap something over the air intakes!

 

[stevd]

Personally I would just remove it to inspect it properly.

 

[sailorman]

Thanks David... that's just what I wanted to know... so I can now try and free the rack, knowing that if it won't move i've identified the problem.

I took the filters off the engine to get at the starter motor to replace it, and discovered that the foam elements had crumbled, so currently, the easiest way to stop the engine in the event of a run away or lack of governing is simply to slap something over the air intakes!

Be very very careful rag can get sucked into the valve train

 

[Phoenix of Hamble]

Personally I would just remove it to inspect it properly.

I almost certainly will, but don't want to spend money on the engine more generally until I know its a viable engine, so just getting her started for now answers a big question.

Thank you everyone for your first class advice and guidance.

 

[Phoenix of Hamble]

Be very very careful rag can get sucked into the valve train

I have one of those foam kneeling boards, that I am using to save too much agony on the joints, that is perfect to create a good airtight seal, covers both inlets, and there's no risk of ingestion!.. should be OK... but always worth reminding me to be careful!!!

 

[stevd]

But the engine won't run with a knackered pump. Inspection will save time in long run, I have been there before, spent many crippling hours bent over the engine doing the exact same thing. Its not fun but mights as well do it. Pumps arent too expensive to service. They are fiddly but can be done diy. As long as u keep everything incredibly clean and follow the process.

But by removing it you will quickly establish if it is the pump or the governor that controls the rack.

 

[lw395]

I have one of those foam kneeling boards, that I am using to save too much agony on the joints, that is perfect to create a good airtight seal, covers both inlets, and there's no risk of ingestion!.. should be OK... but always worth reminding me to be careful!!!

Don't underestimate the full force of air pressure on whatever you might use. It's only 15psi, but it can tear stuff to bits.
Is there a decompressor?

 

[lw395]

But the engine won't run with a knackered pump. Inspection will save time in long run, I have been there before, spent many crippling hours bent over the engine doing the exact same thing. Its not fun but mights as well do it. Pumps arent too expensive to service. They are fiddly but can be done diy. As long as u keep everything incredibly clean and follow the process.

But by removing it you will quickly establish if it is the pump or the governor that controls the rack.

I'd agree with that, if it does not quickly start working.
It could have congealed bio fuel in the inlet for example.

 

[Phoenix of Hamble]

"is there a decompressor"... nope... will have a handy bit of wood nearby just in case ( to cover the intakes, not to whack it with!)

 

[Phoenix of Hamble]

I'd agree with that, if it does not quickly start working.
It could have congealed bio fuel in the inlet for example.

Yes, I did wonder about that, and on top, the fact that water got into the fuel made me wonder about potential diesel bug contamination... but the system was thoroughly cleaned, including the tank, dosed with diesel bug killer before adding completely fresh fuel from a non bio source, and the glass bowl in the filter shows no sign of anything nasty at all... I did remove the inlet union to the injector pump to make sure that fuel was making it that far, so if there is a blockage there, its inside the pump itself.

 

[lw395]

Yes, I did wonder about that, and on top, the fact that water got into the fuel made me wonder about potential diesel bug contamination... but the system was thoroughly cleaned, including the tank, dosed with diesel bug killer before adding completely fresh fuel from a non bio source, and the glass bowl in the filter shows no sign of anything nasty at all... I did remove the inlet union to the injector pump to make sure that fuel was making it that far, so if there is a blockage there, its inside the pump itself.

Is there a tiny gauze filter in that particular pump?

 

[Phoenix of Hamble]

not that I can see... but I am told that there is a check valve in the return union, so that is on my list of things to investigate too!