Fuel supply shortage

[Tea]

Morning all,

With this years warmer weather our standard 1971 traveller has running problems in dense traffic. On my way home yesterday evening everything was fine until I got stuck in a queue and 10 minutes later the car sounded like it was going to cut out. As I started off in 1st it would kangaroo back and forth, same in second, but once in 3rd and moving freely it would be fine. On idle it also sounded and felt very lumpy, with the petrol pump ticking into overdrive. I managed to turn off into a free moving side road and the car drove perfectly after 10 seconds or so, but as I knew I was heading back to traffic I pulled into a car park and waited 30 minutes. The drive home from here was faultless in no traffic and a slightly cooler 7pm.

I had the same issue a few weeks back in the batch of warm weather and so I had cleaned the points in the petrol pump and serviced the carb. The pump does tick like crazy in the hotter weather, but the petrol seems to come through the pipe to the carb as normal.

Would this indicate fuel vaporisation, a petrol pump on its way out, carb issues or something else?

[philthehill]

Fuel vaporisation - fit a heat shield to the up lift pipe below the fuel pump and a heat deflector to the float chamber similar to the heat shield in the link below:-
http://www.morrisminorspares.com/fuel-s ... ly-p830677

[mogbob]

" serviced the carb " quote.
Did this include ? Cleaned out the crud in the float bowl, checked condition of the float needle and valve and it's operation, float level height correct.
Float bowl gasket Ok for further service. Piston free and dropping with a clonk on the bridge when lift pin used. Damper chamber filled with oil. Linkages , cables all free and lubricated. Set correctly. Attachment to manifold tight i.e. no air leaks. Air filter clean. Main jet set up in good condition.
Any extra in line fuel filter fitted ? Clean ? If you have one.

Fuel pump. Points cleaned ......tick. Pump filter taken out and cleaned recently ? Have a new washer " to hand "before you remove. Replace the Plastic filter if at all damaged.
The flexi hose … pump to carb... breaks down internally after years of service. Starts disintegrating internally. The crud can block the carb float needle / weakened rubber pipe partially collapses and pump has to work hard to push fuel through. If filter is "well clogged " you might be sucking up rust from the fuel tank.
Could be simply heat vaporisation with the hot weather we've been experiencing. You can buy heat shields to keep the carb cooler.
Just a few things to think about / eliminate.
Good luck with the hunt.
Bob

[Tea]

Thank you for the replies.

Phil - can you think of why the engine bays heat would be greater this year compared to other years causing the vapourisation? I’d rather treat the cause than the symptom (the heat shield being the paracetamol for a headache, when the headache is from dehydration, if that analogy makes sense??).

Mogbob - carb was serviced as you have stated. I had forgotten about the filter, however. I’ll takes it out and give it a clean replacing the washer if needed. With it only happening when stagnent for longer periods of time I’m assuming it’s not the fuel line clogging, but it could also be a coincidence so will be worth checking.

[RobThomas]

Not all fuels are the same. It seems to go off quite quickly, too.

[philthehill]

The analogy makes sense.
It has been exceptionally warm this year and according to the news the hottest since records began.
I used to have the same problem with a Ford Cortina 1200 way back. If left for half an hour the engine would start.
I would fit the Grumpy's heat shield kit as a matter of course.
The majority of modern cars have the fuel re-circulating so no problems with keeping the fuel cool.
As Rob says above the fuel is not like it used to be and does go off very quickly.
Phil

[KeithL]

We've had this problem in the past on hot days, usually when we have filled with standard Shell petrol as opposed to the Shell V-Power we normally use. Since we have rigorously stuck to V-Power we have never had a problem. Possibly something to do with less ethanol in V-Power?

[Tea]

I’ll get one of the heat shields and whilst waiting for it to arrive will add some of the more expensive petrol. Unfortunately we have 3/4 of a tank of regular unleaded from Tesco at the moment.

Thanks for the help

[Tea]

A quick update in case anyone else has this problem now or in the future - we’ve not fitted the heat shield yet. Instead, we first tried a higher grade petrol (V-Power thanks to KeithL’s suggestion) and the issue seems to have disappeared. This is after an hours run on the motorway at 65+ mph and on A roads followed by a traffic jam in hotter weather than earlier in the week and absolutely no problems. Thought it worth mentioning.