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MG Midget and Sprite Technical - Mechanical Fuel Pump question

My 61 Sprite Mk 2 was cranking over okay but not firing. Fuel wasn't getting to the carbs so I reckon it is a mechanical fuel pump problem. It is an AC Type Y pump. The pump had no fuel in the bowl and I've just removed it. Before I go ahead and order a new one is there any way of identifying visually whether the mechanical pump has a problem? It seems okay to me although there was a bit of grunge/dirt in the bottom.

Thanks
TJ Prime

If the pump is working then when you operate the lever, you should be able to feel suction/pressure against the inlet/outlet when you block the appropriate union with your finger.

Simon
SA Wood

New AC Y type pumps tend to come without a tickler / primer. If you want to fit a recon kit viz diaphrgm, valves, seals & gaskets then Sparex do one. You can get them from your local tractor dealer.
Alan
www.masckent.org
Alan Anstead

Thanks. I can feel some suction/pressure but not particularly strong. I've opened up the pump by removing the screws and the diaphram seems fine enough with no splits. I'll explore websites to see what the options are for new/re-con kits.

Tim
TJ Prime

perhaps the lobe on the cam has worn flat.
graeme jackson

This may be the rebuild kit you need:
http://v2.gb.sparex.com/ItemDetails/ItemDetails.aspx?ItemNumber=40567

Lovely to hear of another MKII 948cc Sprite and in Scotland too!

I have found Sparex parts stocked by my local tractor dealers (Hamilton Brothers in Tarbolton, Ayrshire) so dealers like these may be able to order in such a rebuild kit.

Good info on AC Y Tyle mechanical fuel pump rebuild here:
http://essexdafs.proboards.com/thread/139

and here:

http://www.spritespot.com/Downloads/Workshop%20Manual/D%20The%20Fuel%20System.pdf



Cheers
Mike
M Wood

I have bought a new mechanical fuel pump & fitted it today but sadly the problem is not resolved. I am sure that before I fitted the new pump that there was fuel going to the inlet on the old pump as I needed to keep the fuel line high to stop it spewing out whilst the pump was disconnected. Now there is no fuel going to the inlet and I have a feeling there may be an air lock in the fuel line. When I disconnect the inlet fuel line and drop it as low as I can no fuel comes out. Any good ideas as to how to sort this out? I'm hoping that this is all I need to do to get going again!
TJ Prime

Have you tried blowing backwards into the tank, in order to check for blockages.

Or there may be an air leak in the pipe from the tank.
Dave O'Neill 2

Spent a few hours yesterday helping someone with the same problem.
Car would run a few miles then stop with no fuel in carbs.
Then a shake of the car would allow fuel through.
Undid tank connection and fuel flow was fanned and weak. Dropped tank and what looked like two bits of electrical tape were flushed out.
Alan
Alan Anstead

Thanks everyone. A friend has also suggested putting some fuel in the bowl of the pump to see if that gets the engine firing and this in turn gets the fuel to draw from the tank. I'll try this as well as other suggestions.
TJ Prime

TJ your friend has suggested you 'prime' the pump. Appropriate really!

Let us know how you get on.

After checking dirt in the tank/blocked fuel line. Is there an aftermarket inline fuel filter in somewhere that needs checking? Also you can try pumping with the petrol cap slightly ajar (if there is a fuel tank vent problem). If you have a part metal fuel line, is it squashed?

Cheers
Mike
M Wood

She goes! Did as folk suggested. 1) filled bowl of pump with fuel 2) blew down fuel line 3) left fuel cap slightly open. Nothing at first, didn't fire up at all, just as before. Decided to just keep the starter pull out and leave foot down on accelerator for 20-30 secs. Eventually it fired up! Thanks to all for your advice. Tim
TJ Prime

This thread was discussed between 08/07/2015 and 13/07/2015

MG Midget and Sprite Technical index

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