Well, I finally did the rebuild of the HIF SU's from my '73B. Watched the SU
rebuild tape from Milaw Productions (supplied by Moss). It was exactly what
I needed - took all the mystery out of it!
Anyway, my rebuild was successful, and the car started (in 18 degree
weather, no less) for the first time in at least eight months. I went
through all the set up procedures, but I have a problem that I lack the
experience & knowledge to diagnose.
Car starts, runs, and will move under it's own power, but when I let out the
clutch and apply the gas, the engine loses power and stumbles. Pumping the
pedal a bit will allow the engine to recover, and then it pulls well. So, it
seems to dislike the initial opening of the throttle.
I have checked that the dashpots are correctly filled, and that the pistons
move freely and seat them selves well. I originally had 20W50 engine oil in
them, but given the very low temperatures, I thought it may be too thick.
Cleaned out the pistons and used 3-in-1 oil, but this made no difference.
I used all new gaskets in assembling the carbs, spacers & heat shield, and
have checked for vacuum leaks - none found.
Carbs were balanced using a uni-syn.
Mixture set according to method learned in the tape.
Also cleaned and gapped plugs, replaced cap & rotor, and wires.
Pistons move in equal amounts and in sync with each other as throttle is
opened.
At this point I don't know if I have an incorrect mixture, a dashpot issue
of some sort, or what...
One other thing I noted, I believe relates to the float height setting. This
was the only area of the tape which was not as clear as I would have liked.
I set the float height so that the top of the float (the moving end, not the
hinged end) was 50 thou below a straightedge laid across the bottom of the
bowl. (Carb was upside down and level on the workbench). Anyhow, when
backing the car down my driveway, which is reasonably steep, I noticed the
idle speed would consistantly drop by a few hundred RPM. I don't recall if I
saw this behaviour when the car was running well. Anyway, it makes me wonder
if the float is set properly.
What's my next step here?
--
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Marc Siegel, Charm Net LLC eMail: smarc@abs.net
Baltimore, MD http://www.abs.net voice: 410/361-8160
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