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MG MGB Technical - sputtering

I have recently purchased a car that has spent some time sitting. It idles great, but hesitates then sputters upon acceleration. It has new plugs and wires, a new weber downdraft, new fuel tank and filter with fresh fuel. Any ideas to my sputter?
Seth

Have you got an inline fuel filter? There may be s**t in it that is only disturbed on acceleration. Clean it out, or replace it.
R Lynex

fuel pump not working/blocked.
No oil in dashpots on top of carbs.
K&N filters fitted with no change in needles.
Non-vented fuel cap fitted.
Carb vent tubes blocked (from top of float chamber, steel tubes that go to bottom of engine behind manifold)
Ignition lead breaking down.
Possible problem with points and condenser.
Martin Layton

Hi Seth:

I had a problem where my 72B would idle perfect, but would not go above 15 mph due to sputtering. Turned out to be the condenser was dead, and the points kept fouling. I had to stop every 5 miles and sand down the points with a bit of sandpaper I luckily had in the boot at the time. I was on a 100 mile trip through an uninhabited area, which meant lots of stops before I could get home and order a new condenser, which completely solved my sputtering problem.

As a result thats the first place I'd check...

Erick
Erick Vesterback

Check all of the above (from the previous threads)
first.

If there's no improvement, then try looking at the
pump jets on that Weber downdraft carb. Make
sure that they are clear of obstruction, etc.

If there's an internal fuel filter inside the carb,
you might want to check it, also.
Daniel Wong

The condenser sounds like a likely culprit to me as well.

In addition,as I suggested in another link, it might be worth putting a timing light on to be sure the spark is advancing properly.

John in Music City
John Lifsey

Coil?
Bruce Mills

Didn't spot it was a Webber :)

Has it got an air cleaner? (Likely too lean without one)
Is it the correct fitment and correctly jetted?
Does the accelerator pump work?

(Be careful if you take the top off, IIRR there is a ball bearing in the accelerator pump that falls into the engine if you touch the pedal.)

My old Landrover came with a downdraught Webber. It was a "popular" conversion to get more economy, which it did achieve, by having only a tiny throat, and strangling the engine, so it wouldn't go above 55.

I soon threw that off and went back to a Zenith.

Martin Layton

This thread was discussed between 29/01/2007 and 03/02/2007

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