Ford 3000 diesel 3cyl losing prime when sat

[FordnMassey]

Hi,
I have a Ford 3000 3cyl diesel from 1967, UK build, with a Simms fuel pump priming problem. I've owned it around 2 years, and throughout that time found the fuel system will lose prime if it's not started for some time. Started once a week there's no problem, but at around 2-3 weeks between starts the cranking time becomes noticeable and it starts on 1 or 2 cylinders before building to all 3 over 1-2 minutes. If it is left 3-6 weeks, it simply won't start and needs priming. Once started it runs and works beautifully with smooth powerful, clean running under light and heavy load and at idle. No visible leaks except thru the fuel tap handle shaft, which is slow and improved with a new O-ring.
Anyone got ideas on why it loses it's prime?
Thanks in advance for ideas.
FordnMassey

 

[thepumpguysc]

There’s a couple of things that will cause it..but let me start by saying, It’s normal..
1- The paper valves in the supply pump aren’t seating..
The P# is FP314A
2- the plunger and barrels are worn..
3- there are rubber fuel lines leaking..(sucking air)
It’s a simple starting procedure.. loosen the bleed screw on the head, below the line connection.. use a 1/2” wrench..
Pump the handle on the NEW SUPPLY PUMP.. until fuel and NO AIR comes out and tighten the bleed screw..
Pull the throttle lever off idle and push the excess fuel rod IN.. the rod is located in the middle of the shut off lever..
Activate the thermostart and crank the engine..
I hope this helps..

 

[denchen]

I had a different engine with the same problem. It turned out there was a tiny leak in the diaphram in the fuel lift pump. Diesel was leaking into the engine sump. It might be worth checking to see if the engine oil level is getting higher.

 

[thepumpguysc]

U do know that pump lube(oil) is self contained.??
And needs to be checked several times a year and changed AT LEAST once a year..

 

[FordnMassey]

Hi,
Thanks for the replies, sorry for my being so slow to see them.
PumpGuySC, nice to know it's a common, normal thing. I'll just prime at startup. I have the tips if the problem bugs me enough! I'm not keen to open or rebuild the injector pump unless I have to, especially as it runs so well once started.
Wasn't aware that it the injector pump has it's own self contained lube. I'll read up in my manual and get back if I have questions.
Thanks Denchen, I'll check out the oil level but with my casual checking, I don't think it rises.
Again, thanks for your help. Much appreciated.

 

[FordnMassey]

Hi, An update and some info that may help others.
I got around to draining the lube oil in the Simms injector pump and found the lube sump was full of diesel! I guess I found the priming issue
Does anyone know if this is the lift pump leaking through into the injector lube sump or is this an injection pump issue? I am soon to pull the lift pump down and inspect and will let you know what I find.
Greg

 

[thepumpguysc]

Pn— FP314A supply pump

 

[FordnMassey]

Hi Pumpguysc,
Is that a part number for a lift pump to suit Simms injection?
Thanks for your help
FordnMassey

 

[FordnMassey]

Hi,
Inspection of the lift pump diaphragm shows no issues and I have filled the void behind the lift pump diaphragm and operated the mechanism and can't show the diaphragm to be leaking. I am suspecting it's not the lift pump.
Any thoughts?
Can the injector pump leak diesel into it's sump and still run the motor fine?
Thanks.
FordnMassey

 

[thepumpguysc]

Yes, that’s completely normal. There may be wear between the plunger and barrels that allow the fuel to push past the plunger and into the oil res.
It’s best to shut off the fuel AT THE TANK if u plan to let it sit for any period of time..
When was the last time u changed the oil.?? U should change it 2x a year..