Fuel Pump

[g4zur]

Hi All
I wish to change my fuel pump as I believe it is causing poor starting due to pressure drop.
I would like advice as to change it for a new mechanical or should I change for an electric pump, I see an advantage with an electrical pump as fuel is pumped without having to turn engine over. Is there any disadvantages in electric pumps compared to the std. mechanical one?
Regards
Gareth

G.P.Albrighton

[Workshop Help]

Well, Gareth, in the past four years since my conversion to electric pumping, the only disadvantage is access to the pump should it fail late at night in a thunderstorm with the temperatures hovering in the low 30's F. As the pump needs to be under the car next to the gas tank, jacking up the car to get to it will be a lovely little chore.

Some would say the whine of the pump at idle or at start up is irritating, but I find it to be a reassuring reminder all is well with the fuel delivery system. It's like sitting very quietly to listen to your own heartbeat. If you feel it thumping, you've still got Lessons of Life to learn.

Some folks in the MG fraternity remark a similar fondness for the Lucas solenoid fuel pump as it clicks away pushing gas to the bowl of the carburetors. It's the heartbeat of the engine.

But, knock on wood, both the electric fuel pump and my heart continue to function as the manufacturer intended.

Mildred Hargis

[Hasbeen]

Gareth fuel pressure has nothing to do with the starting, of your car. Your engine would happily start & run for a minute or so with no fuel pump, provided the carb float bowls were full when you first started.

Unless you leave your car for very extended periods without starting it, allowing the petrol in your carbs to evaporate out, you must have a problem in the system, which is probably easily fixed.

How long is it since you cleaned the screen/strainer in the top of your pump? Enough dirt will stop it pumping. Is the pump diaphragm sound, & the valves not full of muck preventing them pumping?

Any change of pump is likely to bring problems with it. Every pump available in Oz & probably elsewhere, [mechanical or electric] is a 4 PSI pump, where as our carbs require a 2 PSI pump. With a new pump this will have to be corrected, or your carbs will flood badly. You do have the advantage of a couple of excellent specialists in the UK who will probably supply a corrected pump, or advise how to correct a new pump.

I prefer the mechanical pump, as something that has operated for over 30 trouble free years has a pretty good record in my book. The fact that Mildred prefers the electric proves there is more than one way of successfully skinning this particular cat.

If you do decide to fit a new mechanical see my current thread "The dreaded miss is back", for details of how to adjust it's output pressure.

Hasbeen

[g4zur]

Thank you Mildrid for your comments, Think I will stick to a mechanical pump.
Hasbeen many thanks also. Starting getting much harder when cold, seems to first start on two cylinders then eventually comes in on all four then runs well. when warm ticks over fine didn't know you could strip the pump to clean (please excuse my ignorance)looked in Haynes manual so I see what you mean, Thanks, Hope after a clean It starts easier when cold, Only just managed to get It started this evening. Could It be something else I wonder?
Regards.
Gareth

G.P.Albrighton

[Hasbeen]

Do you have the linked choke system, with one cable, or the 2 cable system, with one operating the choke on one carb?

It does sound similar to how one of my cars with a twin cable choke system would start, when one cable failed. With just one choke working it did something similar to what you describe.

Could be a hundred things. Do you have points, or electronic ignition? A points system with an almost closed point gap can behave something like that.

Hasbeen

[g4zur]

Thanks for reply Hasbeen, Single choke cable and electronic ignition the electronic ignition I fitted three weeks ago but has been working very well, does seem like a fuel problem to me but I am very much a novice and learning quick lol.
many thanks
Regards
Gareth.

G.P.Albrighton

[Hasbeen]

Hi Gareth. I'd pull the air filters off & check that both chokes are operating together.

I'd also check the suction of the carbs is equal, while you had the air filters off. Just the tube in the ear method is good enough.

I usually suspect something that I have altered recently, when I get a new problem shortly after making a modification. However if you have been following my problems with my ignition system, you would not want any advice on that from me.

Hopefully someone else will advise if your symptoms could be caused by a new ignition system.

Hasbeen

[g4zur]

Hasbeen, Thanks again.
I will do exactly as you say tomorrow (sat) will report back here my findings, hard to start this morning and later 5 hours in between, but during my drive home I had to stop twice. while engine warm it started first turn on four cylinders. Problem is just when its cold, we will see in the morning, Once again many thanks, any more suggestions would be much appreciated.
Regards
Gareth.

G.P.Albrighton

[bmcecosse]

The mech pump is fine -yes - if it's been lying for more than a few days, you have to churn it to get fuel up. But this at least sends some oil round the bearings before the engine fires ! You can fit an electric pump and use it for the first start - then switch it off - or squirt some fuel in the carbs (I do this if starting it after a long rest - ie more than 4/8 weeks..) - or just make sure the battery is maintained with a solar charger if the car is lying unused over winter. Sounds to me like your carbs are a bit leaky -and the fuel is running away too easily. Yes - it starts on the first carb and then as fuel gets to the second carb - it picks up too. But this only happens on my car after say a full week lay-up.

[g4zur]

Thanks for the help. I use the car every day for work, never stands for more than 15 hours, will have a good look in the morning, something else to learn, Must say I am enjoying it though. So you think the pumps ok? That's good. Thank you.
Regards
Gareth

G.P.Albrighton

[g4zur]

Hi all, Update on situation.
I spent a few hours today on car. I first fitted a new fuel filter as there wasn't one fitted, at the same time I replaced the flexible fuel pipe and clips, I then removed the air box and checked all the movement in cables and linkages for movement and balance, BOOM, the linkage for the twin chokes wasn't In balance, under further inspection they were way out, One lock nut was loose and only one choke working, No wonder when cold started up on two cylinders.
Spayed carb cleaner in carbs and all linkages replaced air cleaner and re-assembled.[:p]
Held my breath and turned the key with a little choke [:D]
Started first time ON ALL FOUR, Hope its not a one off, Will update when I try to start again from cold in the morning. I did go for a run about 30 miles, Maybe just me but seems to be running a lot better only time will tell, Once more many thanks to Has been and others for all the help. Next project, Petrol gauge.
Regards.
Gareth.


G.P.Albrighton

[g4zur]

Happy to tell all, Just been out to car, slight choke and fired up first time on all four cylinders, Another job sorted, Many thanks to forum YET AGAIN, Just waiting for the next problem[:)]
Regards
Gareth

G.P.Albrighton