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MG MGA - Misfiring woes 2

Thanks very much to all who took the time to offer help and solutions, all good advice - sorry for the long delay to reply, I was away ....so I haven't had a lot of time to do anything much with the car, then the exhaust "became detached" last week, another problem.... What I did do (before that happened) was to change to new plugs - exactly the same result, misfiring. Tried to release the contact adj screw as the gap looks quite large - absolutely immovable, so I have to work on that one, although it has to be said, the engine WAS running okay with same large gap, before I "renovated" the carbs. I can say the carbs are completely clean, no trace of sediment appearing, and I believe assembled correctly, as per instructions from Burlen, the SU Carb book, MGA AutoBook et al. Of course, this could be the very moment when the condenser finally decides to fail, just that I am trying to recognise the signs...However, I am evaluating what other things have been changed in my carb renovation, apart from ignition causes - 2 key things, 1) I have disconnected the brake servo vacuum from the inlet manifold, and replaced the threaded pipe connection with a stud, sealing the threads to prevent any leak - could this still be allowing a leak at higher throttle, but okay at idle? I thought it was sealed okay.. and 2) I note the vacuum pipe feed to the distributor includes just a rubber pipe push fit (none too tight) onto the steel pipe connecting to the carb. It looks the same as before my renovating work, but again could this cause a problem only at higher throttle?

I will work on these items, and also am ordering new points, condenser etc, will report progress!

Thanks again, Andy
A R S Drinkwater

Andy

Some of your symptons make me wonder if you have done what I did when re-assembling the carbs. Check that you have bolted the rear air filter on the right way round, otherwise you may be blocking an air balancing hole for the piston.

Steve
Steve Gyles

Thats a good option from Steve and well worth checking.
Also anther thing you could check, I had a frogeye brought to me the other day suffering from carb problems. SU being very easy to set up I adjusted the carbs and told the driver to go and try it. He returned claiming it was missing like mad under load. This then took some finding and I removed the filters to visually look at the damper movement. When the throttles were opened the dampers rose at a different rate!! Somehow the dampers had had different weight oil added to each one, not a good idea!
Bob (robert) yes I own an MG Dwarf!

Andy

If the car was running OK before you worked on the carbs, and is not running OK after you worked on the carbc, it sounds very much like the problem lies with the carbs.

Although the standard wisdom has it that 90% of carb problems are electrical, I think that you are in the realm of the other 10%.

James
James Reinhardt

This thread was discussed between 17/12/2006 and 18/12/2006

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