le> MG 4 CYLINDER 1980-75 1493cc Midget ZS-1 150CD 4278 1980-75 1798cc MGB, GT ZS-1 175CD 4278 (1 or 2 Carbs) 1974-73 1978cc MGB, MGB/GT SU-1 HIF 4330 (2 Carb) 1974-72 1275cc Midget (2 Carb) SU-1 HS-2 4330 1972-68 1275cc, 1798cc Midget SU-1 HS-2 4330 MK lll, MGB MK ll, 1300cc MK ll (2 Carb) 1971-68 1798cc MGB MK ll SU-1 HS-4 4330 (2 Carb) 1969-68 1275cc Midget, 1300cc SU-1 HS-2 4330 (2 Carb) 1968-67 1275cc Sedan SU-1 HS-4 4330 1968-64 1275cc Midget MK ll SU-1 HS-2 4330 (2 Carb) 1968-62 1098cc 1100cc MK ll SU-1 HS-2 4330 (2 Carb) 1968-62 MGB, MGB/GT (2 Carb) SU-1 HS-4 4330 1963-61 948cc, 1098cc Midget SU-1 HS-2 4330 (2 Carb) 1962-39 TC/TD/TF/ZA/ZB, SU-1 HS-2, HS-4, 435 Magnette A/A, MK l, ll HS-6 6 CYLINDER 1969-67 2912cc MGC (2 Carb) SU-1 HS-6 4330

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Choke Types

We have 4 different types of chokes, Intregal, Divorced, Electric & Electric Conversion.

Intregal Choke

Integral ChokeThe integral choke is mounted on the carburetor, either near the top, or near the bottom. The illustration shows the choke mounted on the top of the carburetor. The thermostat is heated by a heat tube that runs down to the exhaust manifold. The heat tubes heats up the thermostat and moves the choke valve to the open position. A vacuum passage in the carburetor feeds up to the choke housing and helps pull in the heat from the heat tube. Some of these chokes will also have a hot water jacket running through, or on the thermostat to facilitate heating.

Divorced Choke

Divorced ChokeThe divorced choke typs has the thermostat mounted in the intake manifold instead of on the carburetor. In this illustration, the arrow points to the thermostat which is covered by a metal shield. A rod connects the thermostat to the choke lever, which controls the choke valve to be opened, or closed. As the intake manifold heats up, the thermostat mounted, expands, opening the choke valve.


Electric Choke


Electric ChokeThis is a typical electric choke mounted on the carburetor, which is integral. In this case there is one wire on the choke thermostat. This is the 12v source, which all electric chokes use. The thermostat is grounded via the carburetor itself. Some electric chokes will have a 2nd wire (ground wire), which is connected back to the carburetor. When the key is on the thermostat is heated up, opening the choke valve.

Electric Choke Conversion


Electric Choke ConversionThis is a typical electric choke conversion kit. This is used to convert an integral, or a divorced choke to an electric choke. These choke kits come with a temperature sensor that bolts on to the intake manifold, which provides more accurate choke control than with an electric choke without the gauge. The electric choke conversion kit is not used for a manual choke conversion. The choke housing must be in place in order for it to work.
This choke installs in 20 minutes or less with no special
tools. Remove the old choke thermostat and replace with this choke conversion kit.
Attach the temperature sensor under an existing engine bolt.
Wire the positive wire into the vehicles electrical system. Ground the choke to the carburetor.
Complete instructions are provided for each application.


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