The Fordson Tractor Pages Forum

Hello,
1954 FMD with glass bowl.
Had been weeping but turned to a steady drip today. I had tried snugging up screws with no luck. Diaphragm was hard and separated.
Replaced with new diaphragm. Now I cannot prime it by hand. It was weak before this but I could still get the fuel moving to bleed.
I have good flow from tap.
I did not replace the two small valves as they are missing. If those are the likely culprit I'll look harder for them.
Could I have missed something, or is there anything I can check?
Maybe a new lift pump would be best?

I think you need those valves. You can buy a rebuilt kit or install a new one.

Thanks Mathias. I bought the rebuild kit quite some time ago and managed to misplace those valves, but just found them, along with their respective seals! So I'll have another go of it.
I looked at the valves when I had the pump apart. Do they just get gently prayed out and pressed in place?

There are two screws holding the valves on to the upper body, ensure you fit the valves the right way round and check that the camshaft eccentric is not in the high position. Hold a finger over the inlet port and pump away, you should get a vacuum very quickly. If you don't get a vacuum inspect all parts and try again. I don't recommend you get a new one unless you really need it.
Sandy

Thanks Sandy! I'll give this another shot and post how it goes.
Would lift pump issues cause slower than normal starts? Hyacinth has not had that immediate fire the last few starts.

That could be the case as there isn't enough fuel there if the lift pump doesn't provide it. If it continues after you fix the lift pump it could be other things.
Sandy

Just had same issue with my liftpump (glassbowl type)
Had some slow starts at the onset of winter and decided to rebuild the leaky old liftpump.
Turned out the rebuild kit route would cost about the same as a new unit which the dealer had in stock
The new pump did NOT cure the slow starting which turned out to be over-advanced injektion timing,bit it does deliver a lot of flow for priming the fuel filter (the old pump could barely give a squirt)
Svend

Lack of fuel will cause the same symptoms, but I was assuming that Hyacinth's timing was right, if it's not you'll probably see that the injector pump coupling flange and adjuster have moved relative to each other or that the drive pad has had a large increase in play. In the case of a bitsa engine the timing will have to be worked out by trial and error.
Always pump the lift pump before you start, as otherwise there will be low pressure in the injector pump fuel gallery causing poor starting particularly when it's cold and you need excess fuel.
Sandy

Thanks SvendH and Sandy.
The timing is correct although I'm not sure if wear in the coupler could be an issue.
As far as I know it's the original engine with degrees marked on flywheel.
The primer lever on the lift pump never seemed to have a full stroke if that makes sense-only a slight resistance towards end of stroke.
Hoping Renewing the two small valves in the lift pump solves the bleeding and slower starting.

Turn the engine one revolution and try again, it seems the eccentric is in the high position. Always be sure that the play is fully taken up when you check the timing.
Sandy

Apparantly I did not have the diaphragm rod engaged correctly the first time.
It took a few tries but knew I got it when I felt suction while using hand lever. Installed, bled and Hyacinth fired up nicely, and had fast starts thereafter. We'll see how she does on first start of day tomorrow.
As you stated Sandy, as well as repair manual text and pictures, there should be a small screw that holds a bracket which holds the inlet and outlet valves into top half of lift pump. Hyacinths did not have this, instead they are staked in place.
I was not sure how to remove them and was eager to try pump, knowing it was going to work. I regret not taking a picture.
Guessing the lift pump was replaced with an aftermarket pump sometime in the past 60 or so years?! The large spring under the diaphragm was yellow for what that is worth.
Thank you!

Definitely sounds like an odd pump you have there, Super Billy's one had a brass spring and the plate with screws. Glad to see you're running nicely again.
Sandy

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Here is the old diaphragm, split and hard. I'm assuming fuel could have gotten into the sump? While I could not detect a fuel smell in the oil, it did seem thin so I changed it using the above oil. Any feedback on oil choice would be welcome. I had She'll Rotella 15w40 in her, but reading here get the impression it may not be the best option-too thin etc.
The white screen came with the lift pump rebuild kit and I can't see where it would've been used. Maybe on later model lift pumps?
Thanks again- means a lot to have Hyacinth running as she is my favorite!

It does sound like some fuel leaked into the oil but not much. Either option is fine but SAE 30HD is better as that's what the engine was designed for. The white screen is not a Major part, I don't know what it's for.
Sandy

That screen goes into the top of the later style lift pumps as fitted to leyland and nuffield

Thanks Sandy and John.
My son will be happy to hear we have a part for a Leyland or Nuffield!
We will not get to play with Hyacinth for a couple of days as the temp is -15*C. Too cold for man or machine in my opinion.

Dear god, it was -4°C here yesterday morning and that was too cold for me!!!!

The "feel like" temp with wind chill is -26C according to weatherman. Luckily only lasting through late tomorrow morning.

-15ºC is certainly not too cold for a Major (not even -26, as you might see if you try to start Hyacinth one of these days).
That lift pump looks like Mr. MacGregor's one, I might clean out the spare one we have some time soon.
Sandy

A major might run at -15°C but i'm not sure about the driver, I certainly wouldn't!

Billy26F5 wrote: ↑

Sat Jan 15, 2022 4:05 pm

-15ºC is certainly not too cold for a Major (not even -26, as you might see if you try to start Hyacinth one of these days).
That lift pump looks like Mr. MacGregor's one, I might clean out the spare one we have some time soon.
Sandy

I'm tempted to try, but wonder with that straight 30 oil in such low temps?
It would be good to know.

The oil will heat up quickly, the only one that would struggle is the driver, I would probably struggle too.
Sandy