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Carburettors & distributor


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There is something not quite right I think. Help please.

Carbs

I have a 1969 TR6 Federal model with Stromberg Carbs. I have just serviced the carbs and the car is now running poorly, it feels like fuel starvation.

Now here are the issues - which I am bewildered on.

1st of all the the float chamber plug screws in with a rubber o-ring - I assume that this screws home and is not for adjusting?

The upper air valve has no mixture adjustment - I thought that this would be done via the special allen key tool?

I cannot get the needle assembly out - it is hard in even after undoing the keep screw - any ideas on how this can be removed without causing damage to the air valve?

So, to my confusion - I am now not sure that I have the right air valve / carbs in place - top covers say 175 CD2 whereas the manual states 175 CDSE. Thoughts anyone:unsure:?

Distributor

The Micrometer adjustment nut is missing and therefore it seems to me that the distributor is unstable (not fixed). so I have put a nut on and have adjusted a few times and the timing is now out. So now more confusion on the running issues. I guess that this is a case of setting up the timing? Has anyone change the distributor set up to electronic rather than traditional points?

sorry to share my project - I cannot understand how everything was running so well until I decided to service the carbs - oh why did I make that decision!

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Hi Jamie

I have a 1970 US car with Strombergs. I have found infinite variations on the type and combination of components fitted depending on the emission specifications.

These early Strombergs usually have a fixed needle and an adjustable Jet. The centre screw at the bottom of the carb winds the jet up or down. I have found a good start point (with the air filter assembly removed)  is to check the shoulder of the needle is set level with the base of the piston, via a grub screw in the side of the removed piston. check the diaphragm has no tears or holes, then reassemble. Next wind the jet up or down until the tip of the jet is level with the Carb bridge (steel rule helps) then wind the jet down 2 full turns of the bottom screw. Run the car up to temperature (with the filter assembly still removed) at tick-over carefully lift each piston 5mm or so with a screwdriver, if the revs drop away its too lean (jet too high), if the revs increase its too rich (jet too low), if the revs increase then drop to normal that should be fine.

The above ignores any other issues you may have such as, loose butterfly shafts, bent needles, unequal airflow through carbs (check with a manometer)

 

Good luck and happy Xmas

Peter

 

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If you have fitted one of the simpler Hall Effect electronic ignition systems like Accuspark, you will definitely have to retime with a strobe, its because the magnetic rotor part has the magnets between the cam lobes.

You will also have to balance both carb air flows.

I have a Stromberg manual, if you need some pages copied please let me know.

John

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I suggest that you register and post on a US forum. The resident ZS guru will probably help solve your problem. Since the car ran fine beore rebuilding, trying to adjust the mixture won't help. The air valve from a later carb is plentiful in the US and will have the adjustable needle. The mixture on the early fixed needle carbs can be adjusted by pushing  the jet up or down, but is a pain. Also, many people are going back to points because of reliability issues with electronic ignition replacements

 Here is a link to the Triumph Experience forum-  https://www.triumphexp.com/phorum/list.php?2  

Incidentally, the proprietor of The Roadster Factory, Charles Runyan has passed away.

Berry

 

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