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MG MGB Technical - misfiring

Hello again, you may recall I had a problem with my atarter after putting my engine back in after replacing the clutch, well I sorted that (thanks!) then I couldnt get it to start after various tests this pointed to a faulty condensor I have a spare so I fitted that and it now starts but VERY rough misfiring terribly with bangs coming out of the carbs, I turned off quickly! Any ideas on where to start now? It ran fine before I took the engine out, starting to get a trifle annoying now!
Thanks in advance, I'm hoping some of you more learned types can give me a few pointers!
Graham
G Morriss

Check the thread "how to install distributor"., we've all put leads on the wrong plugs.
c cummins

checked, checked and thrice checked! 1-3-4-2 anti clockwise right?
G Morriss

If the leads are correct, what about the timing and valve clearances?
Allan Reeling

Have you done anything else to the engine?

Is it blowing back through both carbs or just one?
Dave O'Neill2

Strange that the engine was running ok, before it came out. But check as has been said electrics, fuel,( were the carbs removed?) air leaks, vacuum hose back on distributor etc. When you took the engine out, were proper lashing points used? I know it has been said on an old thread the studs can be used, but imagine someone lashing a chain under the rocker shaft!.Maybe a damper piston has got stuck in the carbs? Mike
J.M. Doust

Thanks for your responses, in answer to the various questions, no work was done to the engine bar a clean and a lick of paint, yes the carbs were removed (maybe the problem) lashing was attained by liberal wrapping with rope, vacuumn hose has been replaced.
I intend to set timing (although I can't see how this would have been upset) I have watched John Twists video on the you tube and will use his method (static) and take it from there, I have never checked valve clearences but will give that a go too (using haynes as a guide?) Maybe a strip and clean of the carbs is in order? a little nervous of this I must say, what I can't fathom is that everything was ok beforehand and I can't help but think that I've "done" something within the removal and re installation process.
Oh and yes it is blowing back out of both carbs both in sound and visually (the air filters have not yet been put back on and you can see emissions as well as bangs coming out of both of them)
Agggghhhhh!!!!
Thanks folks, I will keep you posted on progress, in the mean time any thoughts would be greatly appreciated!
Best wishes,
Graham.
G Morriss

Plenty of dud "out of the box" condensors about. Unless you know the replacement is good I'd try YET another just in case. (Distributor Doctor does good ones). Maybe try a new rotor arm too, and check the points gap. Provided all you did was remove and replace the carbs, I'd be inclined to leave them till last or yet more things will have been disturbed. Just check fuel is getting to them and not overflowing from them.
Michael Beswick

I'd double check the sparkplug wires coming off the distributor cap. It's very easy to get a pair 180 degrees out and not even notice it. Also, make sure that you replaced all of the carburetor and insulator block gaskets. This can cause an intake air leak that will result in very rough engine idling. RAY
rjm RAY

This thread was discussed between 14/02/2012 and 15/02/2012

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