Author Topic: Lift pump problems  (Read 5234 times)

Seanw

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Lift pump problems
« on: June 08, 2009, 09:19:33 PM »
I have a 855 CST 1A28-15 with a 4 KW generator, It is new to me and was running when I aquired it. I removed the fuel tank for transporting. The lift pump does not seem to be working, the hand pump will not work as well. I pumped it hoping to see fuel run out the return line, no such luck.... Can I use an electric pump or is the mechanical pump worth a rebuild and how easy is it to get parts in Newfoundland, Canada...

Thanks

prof.blink

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Re: Lift pump problems
« Reply #1 on: June 08, 2009, 11:16:58 PM »
seanw,you might have disturbed tank sedement,wood leaves,paper,plastic and a bug. remove suction fitting,line and fitting on pump and blow through. take off cover on lift pump to check fine screen.you may not be able to reuse paper gasket under cover. blink

oliver90owner

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Re: Lift pump problems
« Reply #2 on: June 09, 2009, 12:07:58 AM »
855 CST 1A28-15  whatever that is....

One can never assume anything, so I will ask: Is the lift pump and hand pump the same thing?  Did you rotate the engine so the pump was 'off' the cam?

see fuel run out the return line,

Which return line? If it is the spill return from the injector, that would not be appropriate.

I would think that if it was working when you aquired it, it is probably not in need of remedial parts.

Tell us a bit more of your engine and your abilities with things mechanical.

Regards, RAB

prof.blink

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Re: Lift pump problems
« Reply #3 on: June 09, 2009, 12:30:50 AM »
olly 90, thats cold. blink

Seanw

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Re: Lift pump problems
« Reply #4 on: June 09, 2009, 08:47:58 PM »
OK, the hand/finger pump is on the side of the lift pump. The tank is clean..When I move the hand pump it doesn't have the pressure that the think it should have...I cranked the engine and held my hand against the hand pump and didn't feel it against the cam but I'm not shore if I should or not. I think the return line is from the injector but I'd have to remove the cover to see. When I removed the engine from its shelter I did notice that the fuel tank was elevated, but I'm not shore if that was for gravity flow or for fueling. I am not a master mechanic but I'm not afraid to tear down an engine, I have a good compliment af tools, pullers, welding equipment and scars....

The engine and generator was on a skid with a self contained fuel tank that had been changed to a seperate tank because of contamination at one point in its life. It is a single cylinder lister ST series.

Thanks Sean

oliver90owner

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Re: Lift pump problems
« Reply #5 on: June 09, 2009, 11:22:40 PM »
OK, I will ignore blink's comments.

Seanw,

Now we know where you are coming from and your ability around engines, we know we are not trying to teach you to 'suck eggs' as the saying goes.

You will not get any appreciable fuel flow from the injector retun.  That carries fuel which invariably leaks past the injector nozzle parts, as they are a close-tolerance metal to metal fit with no other means of sealing 'leak-by'.

The pump may only be a very low pressure device and the spring in the pump (to maintain cam contact) may disguise the difference between operation and non-operation.  Also if there is air in the system you may well be simply compressing the air and not really moving any liquid.  Lift pumps are generally reliable and long-lived and usually only need a new diapragm fitting - OK I have seen totalled ones but as I say generally....

Undo one of the bleed screws on the filter or injection pump and operate the lift pump to see if it is working.  There may be something keeping one of the two non-return valves (in the lift pump) open, if sediment/foreign bodies from the tank has/have got into the line. 

You will need to remove all air from the filter then the feed side of the Injection Pump (IP) and then make sure there is feed into the injector line from the IP.  If air is present anywhere before or in the IP, it will not work properly.

Loosening the injector connector will then help to clear the high pressure lines of air while operating the IP.  Finally when no air is being bled from the system , tightening the injector connection and operating the IP should enable you to hear the chracteristic 'creak' as the injector pops.

When at this point, you should be able to start the engine.

Regards, RAB

abbamovers

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Re: Lift pump problems
« Reply #6 on: June 10, 2009, 12:27:59 AM »
Ditto what RAB said.
Sean I noticed you said you have a hand pump connected to the lift pump.
This may be a source of some trouble.
I had similar problems with a Mercedes w123 turbo diesel that had a leaking hand pump on the lift pump that was allowing air into the fuel line.
I tried everything to bleed it.
Eventually I replaced the hand pump and was able to bleed out the air and get the thing running, but boy did it stump me.
The hand pump should pump up.
You could try bypassing the lift pump/handpump and fuel tank using a another temporary fuel tank held high above the motor, using gravity to bleed out the air.
If this works then you have found your problem.
.
« Last Edit: June 10, 2009, 12:30:11 AM by abbamovers »

Seanw

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Re: Lift pump problems
« Reply #7 on: June 10, 2009, 01:03:29 AM »
Now as we talk about it I did remove a large blob of silicon that was applied to the outer housing of the lift pump around the connection to the block or where the pin for the hand lever is attached...ring any bells?

thanks for your input, I'm gathering info for when I get back at this weekend
Sean

oliver90owner

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Re: Lift pump problems
« Reply #8 on: June 10, 2009, 08:52:37 AM »
a large blob of silicon

All that indicates to me is that there may have been 'tampering' with the lift pump previously.  Whether by a 'wide-boy' or a competent person is always open to supposition.......

Regards, RAB

BTW it is silicone - they make PV cells and transistors with silicon.

Seanw

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Re: Lift pump problems
« Reply #9 on: June 11, 2009, 07:31:22 PM »
Any thoughts on an electric fuel pump?