The large clear container would have to be petrol resistant of course. What I'll probably do is run the car a bit tomorrow, may put in a new set of plugs, over the weekend get a 5 gallon jerrycan from a friend and pump out a lot.

This is the pump I bought three years ago, works fine, just a bit noisy.

https://www.ebay.co.uk/itm/363392093855

That's true about the container but most PVC and similar containers will hold petrol for a sensible amount of time.

I'd hold on putting new plugs in until you solve the petrol problem or at least have got the meths in the tank and driven it a bit. Simple reason being, a new plug might be faulty - it's rare but not unknown - you may have cleared the fault but by fitting the new, faulty plug have unwittingly created another with similar symptoms.

Yes, one change at a time. I had read that a faulty/dirty plug could cause bad idle.

Years ago with my 1100cc Classic Mini, I ran it for decades on Champion plugs, just for a change went to a set of Bosch plugs, immediately a bit of insulator fell off the plug. Amazingly engine was still OK after this. I still have the 1962 Mini (bought it in 1968) and put in a Morris 1100 engine, modified with 12G295 head, duplex timing gears and a single 1 1/2" SU, 3.44 final drive.

The car would easily exceed 100 MPH, still have the Mini.

That was sheer bad luck with the insulator on the Bosch plug - chances are it had been dropped in the shop or somewhere between manufacture and purchase at least.
I had a set of Champion plugs once, lasted about 70 miles. Never again! Also known so many of them misfire from new in others cars that i wouldn't dream of fitting them to anything i owned except in an emergncy - which was why the set i had for 70 miles were fitted.

These days i only use and recommend NGK plugs, had a few "less than good" experiences with Bosch plugs and since i've discovered Honda PGM-Fi and its intricacies, have come to the conclusion that Bosch Jetronic and Motronic isn't as good as it's made out to be!

Sounds like some very useful mods on your Mini (a proper Mini, unlike the new one!), Minis aren't my thing (i find the driving position uncomfortbale) but if i had one i'd be tempted to do very similar but with the 1275cc lump rather than the 1098 and either a twin sequential choke Weber (32/34DMTL or similar) or a pair of 1 1/4 SUs, LCB manifold and a slightly sporty sounding stainless exhaust system.

Take out the electric idle solenoid from the carburettor , pull the jet off the end and look carefully for dirt , I assume it goes ok once you get going and the trouble is only when idling?
There should be an in-line filter in the hose between the pump and carburettor , it was a service item back then .. be very careful when tightening the solenoid , not very tight ...


With the ignition on take the wire off the above solenoid and touch it back on and off a few times , there should be a defined click each time it opens and closes .

Yes, standard Mini seats and driving position are uncomfortable. Actually my Mini has a 1275 unit in it now (from a Vanden Plas 1300, single 1 1/2" version). Not really any more performance than the 1100 (a particularly good build, which I still have.

I did have a Vanden Plas 1300 (twin carb version), beautiful car with all that wood and leather, would move quite fast too. Gave the car away, fool!

Thank you, I'll have to look at the manual to see which this is. I think there is only one electrical wire to the carb, and I thought that was an anti run on thing. The main trouble is idling, but the car is a bit hesitant to drive above idle.

Yes, there is an inline filter, I had though of replacing it. Looks clean, but has been there many years. I'll look for one on ebay.

Its official name is an anti-dieseling valve, also called anti-run-on solenoid, idle valve, idle solenoid and a few others. Usually if it's playing up it will stop it idling completely and also prevent starting, not let it start and idle roughly. Usually they're one of those things that either work or not, no half measures.

Usually if the valve plays up, driving above idle is ok but it won't idle and won't start without throttle.

Thank you, car starts from cold (with choke of course, and that gives fast idle). I do have somewhere one of these valves with the tip cut off. I believe that this was a mod done when the valve fails.

Today, checked the anti-dieselling valve and it clicks when disconnecting the lead when ignition is on. Also disconnected the lead to it when engine is idling, engine stalls, so valve appears to be good. Also removed it from car and applied poer, seems to work OK, gave it a clean away and put it back. Car still idles badly.