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MG TD TF 1500 - 51 TD Carb Question

Hi all,

Fiddling with my carbs this morning because I'm a glutton for punishment, I know she's been running rich but finally getting around to troubleshooting. I wanted to bring to a stall by tightening the needle adjustment nuts and lo and behold I tighten both of them all the way and she's still running, took her for a spin around the block and no issues, very perplexing. What should I look at first? Needle? Gaskets? What?

Thanks,

Steve
SD Denham

First check the float levels are correct, it sounds like they are too high. When you remove the carb domes and the piston / needles, the fuel level should be 1/8” to 3/16” below the top of the jets.
Dave H
Dave Hill

Then check that the needles are set at the correct height. The base of the needle where it begins the first step down should be flush with the bottom of the piston. Lay a straight edge against it to check. Also note what needle size you have they are marked on the portion that sets in the piston. Usually two letters or two letters and a number. Report back your findings or look in the Moss Catalog in the carb section and compare to there list of needles
W A Chasser

Also check that the wing nut on top of the filter has not been over tightened in the past. This can deform the casing reducing the gap inside and choke the airflow. See fig P17 in WSM. The tube in the centre gets pulled up towards the cover.
Ray TF 2884
Ray Lee

I lowered the needles 1/32" in the SU-H4 carbs on my TF to correct my rich / full-up adjusting nut problem.

I also replaced the glands and sealing washer with "O" rings to correct leaks.
http://drive.google.com/file/d/0BxisXBEpc-IWeXFOQzZZQnNScFk/view?usp=sharing

Lonnie
TF7211
LM Cook

When I piy my rebuilt carbs on, it was lean with 12 flats down (putting flow sensor caused an increase in RPM). Went down 3 flats, still lean, another 3 still lean.

Then it got too cold to be outside trying to adjust more, but a quick drive showed it was running OK.

Also tried lifting the piston with a screwdriver as per John Twist videos. Will revisit it when warmer.

Both were professionally rebuilt.

Peter
P G Gilvarry

Peter. Given your chronic lean cond I would be tempt to verify the needle PN and in particular the jet size. If your running an H4 carb someone may have put .090 jets with needles designed for .100 jets. Also I sure the needle is not set too low on the piston

Bill Chasser
TD-4834
W A Chasser

This thread was discussed between 24/02/2018 and 25/02/2018

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