Morris Minor Owners Club

Hi everyone
fitted a new SU pump to my 53 morris 3 months ago and it has cut out a few times recently started with a small tap I was wondering should that happen so early in its life can any lubricant be used on the pivot points or should they be dry i have not disturbed the sealing tapes on the body yet can it be taken off and reused successfully
Ian

Should last a lot longer than 3 months. Guarantee and free replacement spring to mind. Warranty probably goes out the window if you break the seals. Sounds like the diaphragm throw is too short, or dirty points.

Is it a genuine SU pump - or a 'copy' ? The original SU pumps generally last 30/40/50 years - with maybe a new set of points. So something seriously wrong if your's is dying after 3 months. Just check it has a good clean electrical connection and a good earth. And - if you have wisely run the electrical supply to the pump through a secret switch - make sure it is working as it should and the connections are good and tight.

I would take the cap off the end and check that the pin that goes through the bottom is fully through both sides ... if it ever comes out (which it used to on mine until I put a cap on it ... long story) then it will stop pumping ... could be that yours was badly re-assembled?

if its new and all the connections are good, go back to the supplier 1st. You dont want to invalidate any guarantee

its new, original SU, it has only stopped 3 times in last week, started and then fine for a few trips, no secret cut out switch in circuit

Well - you should get that switch asap! As for the pump - either decide to investiaget -or send it back. But once you open it up, you can't really hope to claim on warranty.

Hi everyone
I think i may have solved the problem went to start car after not using for a week and it would not start thought it may have been damp electrics but
not the case the pump gave an occasional click so decided not pump , took top of carb off no petrol in float chamber.Cause needle valve sticking have new one in a carb refurb kit(job for later) will fit now

Well - not heard of one sticking SHUT before! First time for everything.

I had the needle valve gunged up after a lay off which caused the same symptoms. Strip it down and blow it through with the compressor then soaked in carb cleaner, refitted it, and all was good

Aye - but this is a car that was running!

True.... That's why I didn't suggest the float before

Is it a genuine SU pump - or a 'copy' ? The original SU pumps generally last 30/40/50 years - with maybe a new set of points

I've heard of new ones being not so reliable - personally I'd pay £20 for a working old one and £10 for some new points rather than much more for a new one.

The best (and worst) way to check for a faulty pump is to remove the fuel pipe from the carb with ignition on. If fuel floods out then the pump and pipes and filter/s are all fine. The downside is a lot of sprayed petrol (less petrol if you are quick and careful with it). If it sprays whilst you reconect the hose to the carb then not only fdo you have good flow but also a decent pressure.
For health and safety reasons, don't try it, and if you do, have a couple of buckets of water ready (to wash away the small amount of spilled petrol).
To do it safely, secure the end of the fuel hose in a petrol container and switch the pump on - making sure no petrol goes anywhere apart from inside the CE marked petrol container. Don't leave it too long as it can pump a gallon in about 6 to 8 minutes if all is well.

Sounds like you've found your issue anyway, but if you ever need to check fuel delivery in future you'll know the efficient (wrong) way to do it.

I would have taken pipe of carb , except when I fitted new pump as the old pump which i think was off a mini and an SU and leaking from pipe connections (it had two plastic pieces on pump that you fit pipes to) I fitted the correct flex pipe and the thread in the float top was very worn and I could not get a good seal, as I was afraid to put too much pressure on the thread I used a thread sealing compound on it and so I did not want to disturb it. In the long term I will have to look for a replacement top, by the way the pump is an original SU

The Mini pump with plastic fittings is not ideal - it's a 'pusher' pump and the correct Minor pump is a 'sucker'! May be better now to look for a more modern SU carb.

As bmcecosse says the mini pump isn't suitable.
It's designed to be fitted near the tank and is short pull, long push.
The Minor pump is set up long pull short push.
No idea how that's done inside the pump but I do know it doesn't work (although they look exactly the same) because I've tried it in the past.

It works well enough if the Mini pump is mounted low down - either at rear of car beside the tank (that's how it is on a Mini) where it gets doused with water/mud/snow etc, or low down at the front on the engine bay floor. But the exhaust is in the way - so it's not ideal.