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MG TD TF 1500 - Running VERY rich

After running 'Figaro' for about 20 mins I noticed it was running very rich.
I checked the float levels and wound the jets up so they are flush with the gland.
The problem is it will run at about 2000 revs but is reluctant to rev up without hesitation, as though it is too lean.
When I lower the jets by a few flats it speeds up and starts blowing grey/black smoke, as if it's very rich.
The motor has just been rebuilt completely and I'm at a loss to know what to check next!
The needles are GJ as recommended.
The plugs are NKG BP6ES and black when I remove them.
Don TF 4887 'Figaro'
D J Walker

Are you using fresh fuel?
Willem van der Veer

If you have an inductive timing light, connect it to one of the plug wires and run the engine while pointing the timing light at a place on the car where you can see if the plugs are firing evenly. A lot of the problems thought to be carburetor are actually ignition misfiring. Most frequent cause is a faulty condenser, or plug.
Richard Cameron

Thanks Willem and Richard, I've gone back over the archives and found the problem, the floats are set too high.
Dave Braun's description of stting up SU's had the lot.
Oh well, it is the first day of my retirement after 56 years working, maybe the brain hasn't realized this yet.
Don TF 4887 'Figaro'
D J Walker

If you installed the Moss carb rebuild kit, try removing the top washer... Its too thick. Washer #33 in the Moss diagram. Instantly solved my rich issues. This tip was given to me by a MG expert with 30 years experience.
Geoffrey M Baker

Geoffrey and Don -

I have read that the copper washer that Geoffrey mentions was too thick in some rebuild kits.

I measured the "WASHER, top jet bearing (copper)" (Moss part #370-250) that came in my SU Master Rebuild Kit (Moss part #375-518). And I measured the washer that I removed when rebuilding my carbs.

> The old copper washer was 0.033" thick. (too thick)
> The new copper washer in the SU kit was 0.015" thick. (the correct thickness)

Not trying to influence your decision to remove it, just reporting the facts that I observed.

BTW, Don - congrats on setting your floats by measuring the height of the fuel in the bridge. I am still struggling trying to learn how to do so.

Lonnie
TF7211
LM Cook

This thread was discussed on 20/05/2014

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