Stuttering after a few miles then slows down and stalls.

[BenDixon2002]

Even if it transpires the fault is not the pump, it's a good idea to keep one in the boot as a spare.

I also keep a small square of fine Emery paper taped to the adjacent bulkhead, so that I can easily wipe the points in situ (dirty/pitted points being the most common cause when these pumps stop pumping). The old wive's tale of taking the points out and wiping them on a nearby kerbstone strikes me as daft, and fraught with problems.

Thanks for your reply. Coincidence I was writing my update as you posted. Yes, the fuel pump was fine after all. I do keep some emery paper in my car, you never know when you need it.

[philipkearney]

As you have now ruled out the fuel pump, you could confirm it is the fuel line or tank by rigging up a temporary supply and taking the car for another run. If you could set up a gallon tin or similar as a temporary supply, either mounted in the engine bay or similar, this would help narrow things down a bit further if the car runs fine. Probably unrelated, but is the tank vent clear ?

[kevin s]

This is what we did on ours when the pick up kept blocking.

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rps20190202_224925.jpg (69.79 KiB) Viewed 1368 times

Basically moved the pick up into the fuel gauge sender like modern cars, to get it back to the fuel line I had to drill a hole in the boot floor too.

I had to turn up the brass part then solder a couple of pieces of 8mm pipe in.

Obviously we also had to block the original as well a ball bearing will suffice.

It means even if it were to block again just 6 screws to lift it out and clean it.

[kennatt]

If you now have an us pump then they have a filter which ,if you have enough crud to block the pipe,will catch some of the bits and you should be able to see them ,take the filter out and have a look,It seems strange that the fault clears after being switched off and after a while restarts,if the intank filter or pipe blocks then surely it would stay blocked.Without back reading,have you tried a drive with the filer cap off to eliminate no air vent.so causing vacuum in tank .. a known but not common fault ,worth a try before going further.

[mike1864]

In all of this, please be careful with petrol. Remember it (and its fumes) is flammable!

Some years ago there was an account of a man in Wales who decided to empty his petrol tank using a cylinder vacuum cleaner. Two (loud) seconds later it was embedded in the wall of the house opposite.

It hadn't occurred to him that when you compress air and fuel together in a confined chamber and add a spark, you essentially replicate the device that Frank Whittle invented in 1937!

[kevin s]

Before you do anything else it would be a good idea to replace any rubber hose in the line between the tank and the pump with good quality new hose, there is loads of rubbish out there and even decent stuff can soften with age and collapse when the fuel is sucked through, when you stop the suction stops and all seems well for a while, a partial blockage or poor ventilation at the tank end will make things worse.

[mike1864]

Before you do anything else it would be a good idea to replace any rubber hose in the line between the tank and the pump with good quality new hose, there is loads of rubbish out there and even decent stuff can soften with age and collapse when the fuel is sucked through, when you stop the suction stops and all seems well for a while, a partial blockage or poor ventilation at the tank end will make things worse.

A partially crudded tank>pump line certainly seems to be a candidate. But is there any rubber section in this path? There isn't in mine AFAIK. Perhaps also check the copper pipe for any crushing that's limiting the flow?

[oliver90owner]

There is probably less than 0.025Bar (1/2psi in old money terms) between the supply and the pump. I have no idea of the lift capability of the fuel pump, but However manky any fuel pipe might be I would be surprised if the vehicle were to travel several(?) miles before the problem manifests iitself.

I reckon kevin s’s suggestion, for installing an alternative fuel pick-up, is a good one. It is likely the way I would go with such a problem.

As an aside, the bubbles reported by the OP could be a tiny air leak (just before the pump?) or it could be low number ’anes’ (or other volatiles in the modern fuels) coming out of solution under negative pressure conditions. I doubt it was any more serious and would not affect operation normally.

[kevin s]

Before you do anything else it would be a good idea to replace any rubber hose in the line between the tank and the pump with good quality new hose, there is loads of rubbish out there and even decent stuff can soften with age and collapse when the fuel is sucked through, when you stop the suction stops and all seems well for a while, a partial blockage or poor ventilation at the tank end will make things worse.

A partially crudded tank>pump line certainly seems to be a candidate. But is there any rubber section in this path? There isn't in mine AFAIK. Perhaps also check the copper pipe for any crushing that's limiting the flow?

Many seem to have a length of rubber at the tank end where the line has seized into the tank or at the front where a non std fuel pump has been fitted.

[mike1864]

Hi Ben

Was this resolved?

[BenDixon2002]

Hi Ben

Was this resolved?

Hi everyone. Good News!!!

I've just completed a 12 mile round trip, not long I know, but far further than my car used to go! Turns out the problem was either a blockage in the tank or fuel pipe, but I would think it's more likely that the tank was at fault. I've replaced the tank with a new 6.6gal low top tank from ESM. Considering the age of the tank and how often I use the car, I felt more confident in replacing the tank entirely rather than modifying the pickup, but a great idea nonetheless. I have also replaced the fuel pipe with a copper-nickel pipe. There was no rubber section in the previous pipe by the way. If the problem happened again I wouldn't know where to start looking! I would have to start going through the ignition system perhaps, but luckily it hasn't come to that. I also saw another Morris Minor coming the other way on my trip.

Thanks everyone for the help and advice. It would have been a lot more difficult without!

Thanks and kind regards,
Ben

[mike1864]

That's good news.

My own Series II tank will soon be 65 years old. How well does the larger ESM fit? Presumably it doesn't eat into the spare wheel space?

Mike

[BenDixon2002]

That's good news.

My own Series II tank will soon be 65 years old. How well does the larger ESM fit? Presumably it doesn't eat into the spare wheel space?

Mike

Hi Mike. ESM sell both a 6.6gal low top tank and a 9.5 gal tank. I've fitted the 6.6 gallon tank which has a low top like the SII tank, so there is room for the spare wheel. I guess the bottom of the tank must be slightly lower than the orignal for the extra 1.6 gallons, but it's not noticeable and is definitely safe. I know that if you opt for the 9.5 gal there is no room for the spare unless you move it somewhere else.

To get my new 6.6 gal tank to fit I had to do a slight bit of grinding with my Dad. In my case, the length and width of the tank is the same as the hole it goes in, but the corners of the new tank are less rounded than those on the original, so it catches the edges of the hole in the boot when trying to put it in. It wasn't a drastic alteration by any means and it was worth it in my opinion as of course I did need a new tank as the original was in a terrible state inside. I painted where we had grinded with red oxide and went over with black chassis paint from ESM, but you can get the chassis paint from other places. We didn't have to do much grinding - just slightly took the corners out a bit. Once in place, the tank flange and screw holes fit perfectly. Also the tank filler neck is longer than that on the original tank, so we cut the rubber/silicon (I'm not sure what's on mine) filler hose to make it fit. We also cut a bit off the tank filler hose (part of the tank) to make it shorter, but I'm not sure that was necessary.

I hope that helps. I've done 25 miles today with no problems.

Ben

[mike1864]

Cheers Ben

Useful info for anyone contemplating this mod.

Mike