CO 6 for a 79? That's more lenient than the UK which is 4.5 for a 75.
The fast-idle should be 1500rpm, measured on a warm engine, and with the
choke knob only pulled into its full fast idle setting i.e. immediately
before any enrichment begins. My HIFs have a little arrow stamped on the
choke cam and this under the middle of the fast-idle screw just as
enrichment commences (as one cannot see the enrichment device operating on
these carbs) so one would adjust the screws to give 1500 rpm in this
position. On the HS it would be immediately before the jets start to be
pulled down. However on my factory V8 I find the 'correct' position causes
the engine to race, even when cold and on partial choke, and reducing the
choke causes it to stall, so I have them backed off a bit. My V8 does need
full choke for a few seconds if drive straight off whereas the roadster
with HSs needs full choke to start reduced immediately to half choke as soon
as it fires. Both are progressively reduced as the engine warms and will
pull with less choke. Minimum choke should always be used, too much causes
neat fuel to wash oil off the bores causing increased wear and diluting the
oil until it boils off again.
PaulH.
----- Original Message -----
From: "Steve Piepenbrink" <mgbyellow@netzero.net>
To: "MG Mailing List" <mgs@autox.team.net>
Sent: Wednesday, October 15, 2003 5:05 PM
Subject: Emissions
> ... CO 6.0.
>
> My HIF-44 carb has manual choke which I am not used to after having the
Z-S.
> What RPM should the engine run with the choke control pulled all the way
out?
> Mine is about 2000.
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