Sumner Weisman wrote:
> An indication of a too-rich
>mixture can be that you can't adjust the idling speed down as slow as the
>books say. I couldn't adjust mine below 1000 rpm, no matter what I did.
>The problem can also be caused by worn shafts and bushings, allowing air to
>get in. I sent mine out to Apple Hydraulics for machining, and new bushings
>and shafts put in.
I'm not able to get my idle speed below about 1100 or 1200 rpm, unless I
retard the timing. Finding the right ignition timing and/or idle speed for
me is simply advancing/retarding the timingto give an idle speed of 1100
rpm. Retarding the timing enough to bring the idle down to 900 rpm is
great for the idle speed, but at that setting the power SUCKS! Pretty sad,
but the "slow-running" screws on the carbs are backed out as much as they
can be while staying in balance. HOWEVER, the connection you make between
this high idle speed and an over-rich mixture puzzles me a little. Despite
my high idle speed, I've never been able to get a RICH enough mixture.
When I lift the pistons slightly to test the mixture, I get a drop in revs
even with the needles backed out to full-rich mixture. With an over-rich
mixture, this test should yield a brief INCREASE in revs. (while the drop
in revs indicates a lean mixture)
My plan of attack, based on the kind advice from this list, is to raise the
float level a bit, as this seems to be a kind of "coarse" mixture
adjustment. The factory calls for a float height of .625", and that's what
I set mine to years back. But now I think I'll set them to .5" or maybe
.5625" and see if that gives me back some fine adjustment at the needles.
I really should send them off for a re-bushing job, but right now that's
too much money and probably too much downtime for what is a daily driver.
Any other suggestions?
Pete Chadwell
1973 TR6
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