Carb Help

[Moto]

My 64 B is running on 2 cylinders, 1&4. I've checked the ignition system (changed condensor, plugs, points & coil)and all plugs are sparking OK, so assuming it must be carbs. When the engine is running it doesn't like accelerating and keeps back firing through the carbs - suggesting to me that there is petrol getting into 2&3. There is petrol in both float chambers and pistons are dropping OK. Can anybody out there give me some pointers. If so, I'd really appreciate as I'm getting nowhere fast !

Moto

[wildoliver]

If it is running on 1 and 4 then it is definitely not carbs!!!!!

Must be ignition, sounds like your leads are swapped round to be honest, cold possibly be timing but doubt it, could be plug lead degredation but unlikely to be 2 leads, likewise unlikely to be dizzy cap.

I suspect you will find some comedy genius has played with your leads.

Or it could be valve clearances, or possibly headgasket gone between 2 and 3.

Hope it is plug leads!

Where are you anywhere near east yorks?

[wadgebeast]

If you're positive it's those 2 cylinders, then unlikely to be carbs. A sticking piston in one of the carbs does give similar symptoms, but you wouldn't be able to isolate out a misfire in specific cylinders.

[Moto]

Thanks for that - will go check or re-check each of those. I was thinking possible head gasket between 2&3 as well but I've got 140 compression in both. I checked the leads sequence and they're 1342 as per manual. As the car has stood idle for 9 mths, MG Club tech support chap reckons that petrol deposits in carbs is most likely ??? Looks like another weekend with my head under the bonnet..... wey hey !

[wildoliver]

I'll be shocked if it is petrol deposit in carbs, as explained above.

Check your valve clearances.

[Moto]

Thanks for your responses chaps. I'm feeling a bit stupid now but it was your suggestions that got me to go and re-check everything ignition-wise again. Then it clicked 1342 is based on the disi turning anti-clockwise..... der !!

All sorted in 2 minutes. What a waste of last weekend.

Cheers.

[wildoliver]

lol you aren't the first person to do that. we all do it once in our lives!