In a message dated 10/30/2006 12:18:06 AM Central Standard Time,
jimhearn1@comcast.net writes:
> I haven't had my '74 TR6 very long. I had a good carburetor guy (that
> knows
> Triumph twin carbs) adjust the carburetors and it was running pretty good.
> It was running pretty good but had the slightest miss. He suggested that I
> adjust the valves. I did and a few needed adjusting and it ran better than
> ever. We took a trip (appx 400 miles total) and it generally ran pretty
> good but did develop an idling problem. When you would come down from top
> gear for a stoplight, etc, it would either idle fine or drop off and not
> want to idle at all. When you would get it settled down it could sit there
> and idle fine but it didn't like to come down in revs and idle. We went on
> a rally today (appx 200 miles total) and the idling problem is now pretty
> much all the time and the carburetors seemed to load up at lower revs
> (starting out from a stop) but clear around 2500 rpm and fine for cruising.
> Also on backing off (not a lot of pressure) it would occasionally backfire.
When you say loading up do you mean that the carbs are over-rich? If so, I
would start with the float valves in the carbs. There may be debris in the
valves preventing them from closing off all together allowing the bowls to
overflow at idle. Once underway, the car is capable of using all the fuel that
is
slipping past the valves and all is fine. Typical symptoms would be an initial
idle that was OK but getting progressively worse and lots of black smoke upon
take off afterwards.
>
> On the backfire, I would suspect timing but it has run so good with this
> same timing. On the idle problem, I originally suspected the linkage but
> the more I look and the more I read on this board the more I suspect the
> smog stuff. Most all of the smog stuff is still on and since it originally
> was running good I was in no hurry to rip all the smog stuff off. I do plan
> to have it all off eventually. As to the problem that seems to be carbs
> loading up, is it possible that it is a fuel pump or fuel filter or even a
> sort of vapor lock problem (seems like too cool a weather to even consider
> this). Or maybe the smog stuff is my problem all together.
The timing may have shifted on you. If you are running points the points may
be working their way closed because the screw is too loose. It is worth a
check. Also check the cap and rotor and the spark plug gap. These are all
easy
things to check so start there.
There is no smog device that will cause an over-rich situation. But if the
EGR valve is sticking it can cause an idle problem. A quick check is to pull
the vacuum line off of it which will allow it to remain closed during the test.
But any symptoms related to a stuck EGR valve would clear up as soon as the
throttle is opened and air flow increases significantly. It would not persist
until you reach 2500 RPM.
Dave
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