Hi,
One thing I haven't seen mentioned yet is that an excessively lean idle
mixture can cause high temps in the cylinders and thus can lead to run-on
after the ignition is turned off. My TR6 was doing this when I first went
and converted to Webers. $500 worth of different idle jets later, I think I
have that problem solved... Ironically, the car used to do it when it was
almost brand new, so although carbon buildup can contribute to run-on, the
fact of the matter is that run-on can occur even on a "clean engine" if the
temps are hot enough.
If you have access to a exhaust gas analyzer, you might learn if this is
the case with your car.
I'd also try to advance the timing in tiny increments (1 or 2 degrees at a
time) and see of that helps. I have seen some cars exhibit this behavior
whereby they run at the factory timing specs (4 ATDC for later TR6's) that
they run a little too hot.
I'll also point out (as others undoubtedly have) that when the cars were
"leaned out" a bit in the '74 model year, Triumph added a anti-run-on
solenoid along with the carbon canister... it really works, because once or
twice I've left a hose (these would be the big 1/2 diameter hoses that T
into the valve cover, the two carbs and the carbon canister) or left the
wire off the solenoid and the car will diesel when you shut it off.
You might also check that the carbon canister isn't causing any problems...
Speaking of which, has anybody on the list looked into repairing or
replacing carbon canisters???
regards,
rml
TR6's
p.s. Jack - got it. Thanks.
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