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TR6 TR6 carb help

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I

ichthos

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Hello again,
Eventhough my car is running, it is not running as I would like. I am basically a novice, and am trying to learn how to work on this car myself. Currently, I can not get the car to idle below 1500rpm. If I set it below this, it gradually looes rpms and dies. The carbs are kind of sticky. As a result, I have to pull out the choke in town some times. It also tends to skip occasionally when I go up hills. I am considering rebuilding the carbs. My first question is how do you know if the carbs need rebuilding? What is a good source for parts (I have not been impressed by the big three with carb parts)? Am I over my head in attempting this? I am also not clear on how to tune the carbs, or if I have done it correctly. I have an extra set of carbs, so at least I have the luxury of driving while I do this. Does anyone have any suggestions? Any help would be much appreciated.
Kevin
 
One of the first things I would check is the rubber diaphragms for holes. Next would be vaccuum lines for leaks.
The elbow at the bottom of the rear carb, if it gets gasoline soaked, the rubber will get bad and fail.
Next, I would pull the spark plugs(1&6) to see how they are burning. If they look different, for example, one burning white(lean) and one burning black(rich) your carbs may have been played with at one time and could be out of adjustment.
But don't rush into playing with the carbs. Check for an intake manifold leak by spraying starting fluid around the the manifold while the engine is running. If your idle changes with the spray, you have a leak. This can cause the problem you describe.
You must eliminate all possibilities for air leaks that would cause your engine to run lean.
After all avenues have been addressed with no improvement, then you can look at carbs.
Carb problems generally happen so gradually that we never notice a problem. Much the same as ignition problems. Your biggest wear item is going to be the diaphragm, followed by the reservoir and choke gaskets.
People tend to be in a hurry to attack the needles and the balance. These two things tend to remain very constant, and once set should be good for a long time.
You mentioned that the carbs are sticky. Either somebody spilled a soft drink on them or there is a good coating of varnish from old gas on them.
If varnish is a problem, I would take the time to thoroughly clean the carbs inside and out. I would replace the jets and all of the gaskets. Depending on the mileage on the car, I would keep the original needles.
After this rebuild, if the carbs still don't work, I would then work at tuning them.
 
Thanks for the input. To answer some of your questions, I have the original Stromberg carbureters. I checked the damper oil, and the level seems to be fine (I followed the directions in my Bentley manual.) I checked the rubber diaphragms and found no holes. I replaced all the vacuum lines and elbows, since they were quite old and brittle. I don't know if this helps, but there was black soot on the inside of the bonnet above the carbs when I purchased the car. And sorry for the less than technical terms - by sticky I mean that it will jump up or down when idling. For instance if I rev the engine it will stay at 1,000 for a little while and then suddenly jump to 1,500 rpm. Another example is when I come off the freeway - I'll have the choke pushed in, but when I pull up to the first stop, it still idles high at about 1,500 rpm and suddenly drops to 1,000 if I don't pull out the choke, and frequently just dies all together. Even though this car supposedly sat for 25 years, the previous owner did seem to remove all the gas before putting it into storage. I was really quite lucky to have it start at all. I did put in new plugs. Since I have now driven it a few hundred mile, I'll check them out and see if there is any difference. I will also check the intake manifold. I'll get back after I have check these things out. Thanks again,
Kevin
 
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