Stromberg carb sticking pin....query

[Sheepdip]

Looking at the carbs yesterday, theres a small lever linked to each throttle which lets a pin move in/out of body when the accelerator is pressed is sticking shut - think its linked to emmission control? Both were seized shut, managed to eventually loosen with copius plusgas and prodding through inlet, engine seems smoother now, just wondered what the affect of these being permanetly shut would be?

Paul

[brian0443]

Also wondering Paul. I noticed the same about three weeks ago, but only had one sticking. Like you I think the engine is running better, now that they are moving freely, but apart from the fact that they are working I haven't a clue what they do.
Brian

[Arbman Al]

Hi Paul & Brian,

The part you are talking about is the vent valve.

See this thread for some good info:-

http://www.stag.org.uk/forum/showthread.php?12723-Stromberg-setting-up&highlight=vent+valve

Cheers....Al

[Dieter H. Marschall]

Hello,

All these items like vent valve, temperature compensator, etc. were only introduced to meet the US emission control laws. Personally I reckon that they were all a "pain in the neck".

Stags were not built as long as TR6s. So on late US TR6s you can find even more of the US rubbish. Most European TR owners get rid of most of these items as soon as possible.

After I have replaced the Stromberg carbs on my Stag by SU HIF6s I am ever so happy I did it. SUs are much simpler. Thus they could not meet the US regulations. But who cares?

Best wishes,
Dieter.

[Sheepdip]

Thanks Al and Dieter, pays to do a search as very recent articles. I still don't see exactly what it does other than its a vent for bypassing the closed butterfly? Does this let more air in on tickover? If thats the case then guess it would have a marginal, but very small affect when throttles open. My symptoms were a rough idle but more that when I accelerated there was an initial lag, rather like the dashpots were empty, but feels better now. That said I also changed the plugs!

Cheers

Paul

[V Mad]

As Dieter says, they are related to emission control for US regs.

At engine idle, the valve opens to vent the float chamber externally via a rubber pipe (these are simply open to atmoshphere in UK cars). When throttle is opened, this vent closes and the float chamber is then vented through internal drillings which then lead to the air cleaner. If one of them is stuck, this might slightly unbalance the pressures in the float chambers but I think it is unlikely to have any noticeable effect on running. Perhaps to be safe, they should be disabled ie adjusted to always be in one position only.