Fellow Listers:
Just got my newsletter from the local club, and this was in it. Thought
it might be helpful to some of us.
<center> <bold><bigger><bigger><bigger>S U Carb Tech Note
</bigger></bigger></bigger></bold>reprinted from mgTalk Volume 23 Number
1
by Dick Martin
</center> In the Tech Tips section of the Winter 1990 edition of Moss
Motoring, Robert Koval submitted an article on "SU Rebuild Kit
Installation". The article addressed problems associated with trying to
adequately lean out SU H-series carbs, especially after installation of a
carb rebuild kit. The problem results from failure to completely tighten
the jet securing nut. This results in inadequate compression of the cork
seal between the main carb body and the cupped washer above the jet
securing nut.
When properly compressed, the gap between the main carb body and the
cupped washer should be approximately 0.5mm (.020").
Why is this important? Because the jet can't reach its full upward
extension into the main carb body unless the securing nut is properly
tightened and the cork seal properly compressed.
When properly assembled, the cork seal will conform to the depression in
the cupped washer, and the jet assembly will be correctly positioned in
the main carburetor body. The cork seal must be spongy and pliable so
that it will "cold flow" into the cup of the washer.
Years ago, Blair Engle advised me to soak all the cork seals and gaskets
in light oil for several days prior to carburetor assembly. The oil soak
makes the cork seals and gaskets pliable for easy assembly (if the cork
is dried out, it tends to crumble when assembled and tightened or
compressed). Blair keeps a small jar of light oil on his shop shelf to
store his cork seals and gaskets.
In recent years, a number of us have had problems with running too rich
and not being able to lean it out sufficiently. While this may be due to
the viscosity of our new gas, as some have suggested, it would be
worthwhile to check if the problem is the jet nut, as above.
This is a direct copy from the newsletter, so I can't accept any praise
(or condemnation!) for its content. I believe Blair is reading the list.
If so, Blair, your comments and advice are welcome!!
Sam Staton
73 Rdstr
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