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MG MGB Technical - No power on the low end

I just got a 1972 MGB from a co-worker who did not know what he was getting into.

He had the clutch replaced and the mechanic he used removed the engine and it has not run very well for him ever since.

I replaced the points, wires and plugs and it started to run better. I found that both air filters were old and dirty - and one looked as it it had burned 70% of it away - I assume from the back firing.

Right now - when it is warmed up - I get no power in the low end of 1st gear - pretty good power (not great) from there on up. When it is cruising along with little gas, it coughs and sputters quite a bit.

I am not the greatest with MGs - I am still learning, and lucky for me, I like to learn by working on them!!
Where do I go from here?
John Forness

I think the next items to check / adjust are: timing, mixture, carb balance, and valve clearance. If you don't already have a service manual, you should pick one up. If it has sat for a long time, the carbs would likely benefit from a good cleaning. Take the plugs out after a good run to roughly assess how close the mixture is by looking at the plug colour. Keep us posted!

Dave
Dave Whitehead

In addition the the above, it may be worth checking for a vacuum leak at the manifold or off any of the pipes coming from it, especially if it ran OK before the clutch job.
Steve Postins

Of course, with a slipping clutch, the engine wouldn't have been under full load in any case. check for wear on the carburettor butterflies and spindles. thes can cause an over lean mixture. Also investigate wear on the jets and needles. I had a car that produced no power below 3000rpm and then full power over 3000rpm due to worn jets and needles. Made pulling out of junctions exciting...
dave

John, I would agree that checking the timing is next order of business. Remember to accelerate the engine with the timing light affixed to determine that the mechanical advance is working properly.
Regards,
Dennis
D F Sexton

You need to do a full setup of valve clearances, plug gaps, points gap/dwell, timing, centrifugal and vacuum advance operation, and carb air flow and mixture balance. That is after making sure there are no faulty or damaged parts, vacuum leaks etc.
Paul Hunt

This thread was discussed between 14/02/2005 and 15/02/2005

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