Free Carburetor Repair Manuals

Manuals are downloaded as PDF files. Some are very large and might take some time to download, depending on your internet connection.Please do not distribute these manuals. Instead giving out the link to this web page would be appreciated. Link is as follows: keep in mind that these manuals may span several carburetor models and may not be your exact carburetor. Use these manuals as a general reference only. Don’t forget to visit the technical pages for your specific carburetor. More manuals for specific carburetors may be available there.


Autolite, Ford & Motorcraft Manuals & DVDs

Carter AFB Carburetor Manual
Carter AS Carburetor Manual
Carter BB Carburetor Manual 1938 & Prior Also works for bbr1
Carter BB Carburetor Manual 1939 & Later
Carter Brass Bowl Manual
Carter BBD Carburetor Manual
Carter Divorced Choke Adjustment – Older 1955
Carter RBS Carburetor Manual
Carter Thermoquad Carburetor Manual
Carter UT Updraft Carburetor Manual
Carter W-0 Carburetor Manual
Carter W-1 Carburetor Manual
Carter W-1 Climatic Control Carburetor Manual
Carter WA-1 Carburetor Manual
Carter WCD Carburetor Manual
Carter WCD Carburetor Manual – 1962 Rambler – In general, this is ok for any WCD
Carter WCFB Carburetor Manual
Carter WDO Carburetor Manual – 1938 & Earlier
Carter WDO Carburetor Manual – 1939 & Later
Carter WGD Carburetor Manual
Carter YF Carburetor Manual – Older YFs
Holley 94 Carburetor Manual
Holley 740 Carburetor Manual
Holley 852-FFG Carburetor Manual

Holley 885 Carburetor Manual
Holley 885-JJG & 885-JJGC for General Motors Trucks
Holley 1904 Carburetor Manual

Holley 1908 Carburetor Rebuild Manual
Holley 1920, 1940, 1945, 2210, 2245, 5200, 5210, 5300 Carburetor Manual
Holley 1940 Carburetor Manual
Holley 2110 Carburetor Manual

Holley 2300 Corvette – 1968-69 Tripple Carburetors
Holley 2300 Carburetor Manual
Holley 2300 Carburetor Rebuild Manual – from a 1962 repair manual.
Holley 2300C, 2300G, 4150C, 4150G, 4150MG, 4160C & 4160 w/mechanical secondarys
Holley 4000 Carburetor Manual
Holley 4000 Visual Instruction Manual
Holley 4150C Carburetor Rebuild Manual
Holley 4150EG Carburetor Manual
Holley 4150EG Governor Manual
Holley 4150G Carburetor Manual
Holley AA-1 (electric choke) GM Trucks Carburetor Manual

Mercruiser Weber Marine Carburetor Manual

Motorcraft 2100 4100 Carburetor Manual
Motorcraft 2700 7200 Carburetor Manual – large file, but great manual.

Rochester 2G, 2GC Carburetor Manual
Rochester 4G, 4GC Carburetor Manual
Rochester AA Carburetor Manual
Rochester B, BC, BV, AA, BB Carburetor Manual – Be patient, this is a large file.
Rochester BC – Published in 1951
Rochester Dualjet Carburetor Manual
Rochester E2SE Carburetor Manual
Rochester E4ME-E4MC Service Manual
Rochester Monojet Carburetor Manual
Rochester Triple Power Pack Manual
Rochester Quadrajet Carburetor Manual
Rochester Varajet Carburetor Manual

Solex 44PA1 Rebuild Instructions
Solex 44PHH Carburetor Manual
Solex Selection and Tuning of the Carburetor

Stromberg AA Series Description & Operation
Stromberg used on Government Vehicles AA, SF, BXV
Stromberg Service Manual – many Strombergs represented here.
Stromberg WW Carburetor Manual
Stromberg WW Carburetor Manual 1955 Edition

SU – Servicing, Testing & Repairs   Zenith 28 228 Rebuild Manual

Zenith 63M 263M Marine Rebuild Manual
Zenith Gov-U-Retor Specification Chart
Zenith Gov-U-Retor Service Manual  

Marvel Schebler

Recent Posts

Injector Types

Different Injector Types – How Do They Work?

You have probably been driving your car around for years without giving too much thought to the principle of action behind the engine. You don’t need an engineering degree to understanding the basics of an engine. The purpose of a gas-based engine is to transform controlled fuel explosions into kinetic energy, which is further transmitted to the wheels through a gearbox. The fuel is collected through a fuel pump from a tank then it’s delivered and injected into the engine.

The injector



A critically important component within the injection mechanism is the injector. It sprays a finely tuned amount of fuel into the ignition chamber where a piston compresses it then a spark plug makes it explode and create kinetic energy. As previously mentioned, the amount of fuel sprayed by the injector is highly tuned by the ECU (electronic control unit). Any variation would prove to have a considerable impact over the vehicle performance, usually lowering it.

In order to optimize performance based on the type of fuel used, purpose of the vehicle and to adhere to the latest technological improvements, more than one type of injector has been developed. Currently there are 3 main injector types being used in automotive engine construction: top-fed, side-fed and throttle body injectors.

Throttle body injectors (TBI)

Initially introduced in airplane construction, throttle body injectors are also called single point injectors. Unlike their more Throttle Bodymodern counterparts, single point injectors are located directly inside the throttle body rather than on a rail.

They were the first upgrade of the classic carburetor system, and thanks to its design, a throttle body injection system can make use of mostly the same components as the carburetor did.

Along with their compatibility on older carburetor based throttle systems, throttle body injectors are also relatively cheap to repair or replace when compared with the other available injection systems. However there is also a drawback. Although computer-controlled, due to their emplacement and way of action, throttle body injectors are not very efficient. The fuel is dumped into the intake, creating what is known as a “wet manifold”.

Multi point fuel injection


Also known as port injection, multi point fuel injectors are designed to work as a group, with each engine cylinder having a fuel injector of its own. Injectors are placed right outside the intake valve, the fuel vapor is ensured to be delivered completely to the ignition chamber.

This allows a better tuning of air/fuel ration while in the same time it lowers chances of fuel condensing inside the manifold, as it Injectorsometimes happen with the throttle body injection systems.

Even with the high proximity placement of the injector, multi point injection systems still lack a perfect suction of the fuel inside the ignition chamber; it is however, more effective than TBI systems.

Sequential injectors


Based on the multi-port injection system, sequential injectors are also assigned one per each cylinder and attached as close as possible to the intake valve. However, unlike regular MPIs, sequential injectors are controlled individually by the ECU (electronic control unit), allowing them to open one at a time.

Sequential injection allows for fuel to be delivered solely when the intake valve opens so it directly travels inside the cylinder chamber. In case of regular MPIs, all injectors fire at the same time regardless the state of the intake valve. Sequential injectors can be timed to spray fuel in the same manner spark plugs are set to ignite it.

Fuel economy is increased with the use of sequential injectors. However, incomplete fuel consumption may arise when injectors are poorly tuned, leaving traces on the intake manifold or over the surface of the valve.

Direct injection


Used on more recent engine types, direct injection systems bypass intake manifolds and valves, spraying fuel directly inside the Injectorignition chamber. Computer-controlled, direct injectors are timed to spray fuel differently according to engine type.

Diesel fuel is injected either through a high-pressure common rail connected to injectors. The other option is to use unit injectors which increase the pressure of the fuel within the injector rather than within the common rail.

Ultra lean burn is achieved when using direct gasoline injection (also known as Fuel Stratified Injection – FSI, or Gasoline Direct Injection – GDI) while also completely removing “wet manifold” issues and reducing emissions.

Although they provide more performance and better fuel efficiency, direct injection systems are also more expensive to repair or replace when damage occurs.


Side-feed and Top-feed injectors


Along with emplacement injection type, fuel injectors also differ according to the way fuel is supplied to them. Injectors can be either is supplied with fuel from the side (side-fed) or from above (top-fed). While the overall aspect may not look very different to the naked eye, there is a series of advantages and drawbacks for each type.

Side Feed InjectorTop Feed Injector

Side-feed injectors are fit inside the common-rail. The rail is fixed either to the engine block or the manifold. Side-feed injectors are constantly surrounded by fuel; given this, they benefit from improved cooling, thus being less prone to damage. The side-feed is the most common used injector type.

On the other end of the barricade are top-feed injectors. Unlike their side-feed counterparts, top-feed injectors are attached between the rail and the cylinder chamber. This makes them easier to replace or upgrade, as there’s usually no need to adjust or replace the common rail as in case of side-feed injectors. However, due to the fact that they are not surrounded by fuel at all times, top-feed injectors may suffer from a lower life expectancy, needing to be replaced more often, especially in high-performance vehicles.

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