MG Midget J1 1933 Instruction Manual page 76

regulating the jet opening.
If
the piston is sticking this can c:lsily he ascer-
tained by inserting
:I
finger i n the air intake and raising the piston.
'l'he
piston should come up quite freely and return to its seat with a click as soon
:IS
i t is rcle:~sed.
A large percentage of the c:lrhuretters returned to the Works for
correction li:~\,e had the jet removcd and repl:lced without being correct11
centred.
O n no account should the jet he tanlpered with.
It
is quite ;In easy matter to bend the needle
if
the piston is : ~ t any time
renloved, in \vhich c:tse i t
\vill
hind on the jet : ~ n d cluse the piston to stick.
To
ascertain
i f
the needle is bent-providing the jet is not out of centre-
rcnlove i t from the piston, refit the suction chamber on to the body of the
c:~rhuretter And see
if
the piston falls freel!..
If
the n'eedle is bent the only
s:~tisf:~ctor!. remedy is to replace i t by
;I
new one.
Float-Chamber Flooding.
This is usu:111y obvious from the quantity of
petrol flo\ving over the float-chanihcr and dripping from the ; ~ i r inlet.
Flooding is gener:~lly c ; ~ ~ ~ s e d
h!.
foreign matter finding its \vay o n to the
sc:~ting of the flo:~t-ch:~nlher needle. I t can sonietinies he removed
flooding
the c:~rhurettcr \ v i t h the tickler pin, thus permitting the inconling petrol
stream to \v;~sh :i\vay the particles of grit, otherwise :Iccess to the n'eedle is
oht;~ined h!. r e n ~ o \ , i n g the flo:~t-chanibcr top
:IS
pre\~iousl>. (1esc.1-ibed. T o
take
O I I ~
the needle i t is necessary first of :l11 to t:~ke out the pin which holds
the needle guide i n position. After t:lking :~w:~y the guide the necdle will
drop str:~iglit o u t ; the sc:~tirig should on no ilccount be ground ill.
Synchronisation of Carburetters.
Reforc attempting to adjust the car-
hurett.c.rs, i t is advis:~hle to check over the following items.
Ignition timing.
Set the
1
and
4
mark on the flywheel : ~ t T . D . C . Put
the distrihutor in the fully retard position when points should he just
o n
the
moment of opcning. Ilistributor and plug points should he checked for
cle:lnliness and gap, i.e.
.020"
on distributor :~nd
.025"
on plugs, ; ~ l s o valve
cle:~r:lnce should be
,004''
betlveen base of c:lm : ~ n d rocker.
klaving checked these items, remove the dash pot covers And the dash
pots from the c:~rhurctters, disconnect the jet coupling rod :\rid screv the jet
:~djusting nuts right up.
On
pushing the jets up to the full weak position
the correct petrol level bhould he
1
mm. below the top of the jet.
I f
this is
not so, and assuming the floats are
i n
good condition and not p u n c t u r d , the
level can he :~tljusted
h!
hending slightl! the guide controlling the float needle.
up to raise o r down to Io\ver, whiche\,er is required. Next proceed to het
the needle i n the dash pots.
In the case of the N o .
1
-r. AC the s t ~ o u l d e r of the needle should be flt~sh
with the dmh pot or piston. Refit the dash pot and cover to the carburetters,
making sure that, when scre\ved down tight, the d:~sh pots will
f:111
on to their
se:~tings with :I click. Screw down the,jet adjusting nuts two complete turns
and screw
o~ slo\v ru nr~ing rod : ~ n d butterfly adjusting screws so that t t ~ e y
:Ire
1 1 0 t
in use. I'Ile~l sl:~cken one butterfly flexible coupling holt, press both
butterflies h ; ~ r d closed 2nd retighten bolt, m;~king sur'e neither butterfly
nloves during this o p c r : ~ t i o n .
J
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PAGE SIXTY-SEVEN