Engine stopped.

[mike1864]

The weather was too naff to try anything today. And the job is suspended for the weekend; birthday events taking precedence.
But there's definitely a drain plug under the tank.
Meantime I had a sniff of the liquid that came out of the pump earlier in the week. It smells more like turps than petrol!
The good news is that my local MOT garage is happy to take the old stuff off me.

[philipkearney]

Hopefully fresh fuel solves your problem. The new fuels go off very quickly. Last spring my ride on lawnmower would not start after being taken out of storage for the winter. Tried everything and eventually drained the fuel out, put fresh fuel in and it fired up straight away. The petrol in it was only 6 months old but had gone off. If your fuel has been there since 2023, I'm sure that'll be your issue. Fingers crossed.

[mike1864]

While waiting for the time and weather to implement the above, I've been doing some research and calculations.
The internet and my own experience seem to suggest that petrol may lose around 0.1% of its mass per day via evaporation.
(Of course this is highly dependent on a range of factors!).
On this calculation a typical Minor tank may lose 8-10 litres a year, regardless of annual mileage.
This will obviously impact the mpg.
Forty years ago my other Minor (convertible, which I still run!) was doing 12000+ miles a year, daily commuting from Hertfordshire to West London. So 9 litres lost in 350 is not significant. But for lower annual mileages, this "angel's share" will impact the overall mpg.
In the extreme case of my Traveller (45 miles per year!), its 17 month average is down at 14mpg. And currently zero mpg, on the residue now left in the tank.
Keep using it up within 6 months is the moral of all his!

[svenedin]

While waiting for the time and weather to implement the above, I've been doing some research and calculations.
The internet and my own experience seem to suggest that petrol may lose around 0.1% of its mass per day via evaporation.
(Of course this is highly dependent on a range of factors!).
On this calculation a typical Minor tank may lose 8-10 litres a year, regardless of annual mileage.
This will obviously impact the mpg.
Forty years ago my other Minor (convertible, which I still run!) was doing 12000+ miles a year, daily commuting from Hertfordshire to West London. So 9 litres lost in 350 is not significant. But for lower annual mileages, this "angel's share" will impact the overall mpg.
In the extreme case of my Traveller (45 miles per year!), its 17 month average is down at 14mpg. And currently zero mpg, on the residue now left in the tank.
Keep using it up within 6 months is the moral of all his!

Interesting. The Minor has a vented fuel cap as you know. Perhaps you could put a plastic bag under the lid and screw it down to reduce the evaporation if laying the car up for an extended period of time?

Stephen

[mike1864]

I'd rather not make any petrol storage hermetically sealed. I once left a full plastic Jerry can in the sun, only for it to become so bloated that it sprang a pinhole leak. My Traveller sits in the sun; so I'm happy to let it vent.
Aside from which, I understand that evaporation is only one vector of petrol going off. So combating it won't address the phenomenon of staleness. The answer is simply to use the petrol quickly. My problem was that I never PLANNED to lay the car up; we simply didn't happen to use it much for over a year.
It's just that this "angel's share" may mislead some owners into thinking their low mileage car is less fuel economic than it really is.
Consider two identical Minors going on a 150 mile run, both filled to the brim before they set out. High annual mileage Car A fills up at the end of the day, getting 4 gallons in, and so reporting an mpg of 37.5.
Low mileage Car B also used 4 gallons but doesn't get filled up at the end of trip (the owner perhaps thinking he doesn't want a whole tankful going "off"). Six months (and zero extra miles) later he fills up, replacing not only the 4 gallons used on the trip, but the one gallon that evaporated since. So the owner reckons his consumption is 150/5, ie only 30mpg.
Car A would have lost the same one gallon over that six months, but that loss never featured in the trip calculation; and would have gone virtually un-noticed amongst all its subsequent fillings.

[svenedin]

You'll never get a Minor petrol tank hermetically sealed. The fuel sender gasket is only a thin piece of cork after all....There's also a breather hole in the carburettor float chamber lid.

I had problems with fuel going stale in garden equipment over Winter. The equipment would not start in Spring and I also noticed corrosion in the aluminium alloy carburettors. I started using a fuel stabiliser and I have had no problems since. I use it in the Morris too.

Stephen

[myoldjalopy]

It would appear that the old adage 'use it or lose it' applies to modern petrol as well!

[Mervin]

Just a bit of an update. It's still a mystery. Went out in the car a couple of weeks ago, short trip, nothing happened. It's been started and run a couple of times since. Not ideal, but out and back into the garage too. Instant starts, ran fine.
Took advantage of dry roads and sunshine, this morning, a bit longer run out. Nothing has been replaced so far. Once on the main road, 40mph still with a bit of choke, it definitely hesitated/misfired a few times but didn't stop. Then ran perfectly until back home.
Certainly feels like an ignition issue. I really don't expect there's a problem with the D.D.'s distributor?
I might chuck a new coil on. The existing is newer "Lucas", probably best Chinesium.

[svenedin]

The old adage was "it's never the coil" but people have had problems with modern coils where a wire inside intermittently makes and breaks contact causing misfiring. If you want to ensure reliability and longevity with a coil, Distributor Doctor recommends Pertronix coils. You can buy one of those that is filled with epoxy rather than oil. These are particularly vibration resistant for the on top of the dynamo mounting position. Expensive of course but should last a very long time. Note, a new larger coil bracket is needed as the Pertronix coils have a larger diameter. It is also possible with these coils to increase the spark plug gap to take advantage of the extra output.

Stephen

[mike1864]

Apologies for the delay in reporting back (naff weather, then a a bad cold).
But I drained the tank; 5 Litres via the pump, then another 5L out of the tank drain hole.
Then 4L of fresh E5 rocked around the tank in 1L steps.
These flushes were progressively less cloudy coming out.
I filled the float chamber with fresh E5, and it started!
So the 18 month old E5 (probably Morrisons FWIW) was the cause.
I'll refill over the weekend.
The other Minor runs OK on 9 month old E5. But I'll try and use that up asap.