Mike’s Carburetor


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VW Fuel Injection

By the mid 1960s, mechanical fuel injection had been successfully employed in Formula One and sports car endurance racing for more than a decade. But manufacturers were just beginning to install it on production cars. Volkswagen introduced it first in 1967 on what the company referred to as the Type 3: the notchback, squareback, and fastback models. It was a Bosch system called D-Jetronic. Volkswagen would not introduce fuel injection to the rest of its line-up until 1975, when they switched to the Bosch L-Jetronic system for their Beetle, Super Beetle, and Type 2, better known as the Bus.

Bosch had developed a direct injection system for gasoline engines as early as 1952, for the Goliath GP 700, a misnomer if there ever was one. The Goliath was a tiny car only 160 inches long, and production numbers were low. The VW Type 3 was the first production model built in sizable numbers to sport mechanical fuel injection on gasoline engines.

These were simple systems, but all systems break down over time. And forty years is a pretty long time. Today, parts are increasingly difficult to find, especially for the earliest D-Jetronic system. Even finding mechanics experienced with these early systems can be a challenge. Some owners prefer to go the DIY route. And some convert their engines to carburetion instead. There are useful manuals out there for the DIY-ers. One that is a little pricey but very helpful is Bosch Fuel Injection and Engine Management, by Charles O. Probst.

Several aftermarket companies make replacement “bolt on” fuel injection systems, but installation is typically far more complicated than merely bolting them on. They may require some drilling, fuel line modification, and perhaps welding of the O2 sensor. You have to be a pretty ambitious DIYer to tackle this job. And the initial cost of these systems can also be prohibitive. Some of these do come in kits, however, which help to simplify the process. For the truly ambitious DIYer, you can always build a system from scratch. But that will involve not only the new fuel line, but also the pressure regulator, electric pump, throttle body and its sensor, a computer, and of course, the injectors. And anyone ambitious enough to consider going this route has probably already replaced the Bosch system.

There are many paths you can take to put your VW back on the road, some far more elaborate than others. A lot of it is simply deciding what is best for you, your car, and your pocket book.

Subaru Class Action

A lawsuit has been filed in the United States District Court in New Jersey against Subaru of America, Inc. (“Subaru”) and Fuji Heavy Industries, Ltd.

What is the suit about?

The suit alleges that certain Subaru vehicles suffer from a design defect that causes them to consume excessive amounts of engine oil. The lawsuit seeks class action certification for people who currently own and lease the affected vehicles, as well as for people who previously purchased or leased the affected vehicles. The suit alleges that Subaru violated certain consumer statutes and breached certain warranties to its customers.

Subaru denies the suit’s claims, maintaining that it has not violated any warranties, statutes or laws, and maintains that the vehicles in question are not defective.

What remedies are available?

Unless they exclude themselves from the class action settlement by June 13, 2016, eligible Subaru purchasers/lessees are eligible for the following remedies if the court approves the proposed settlement:

  • Cash reimbursements for expenses not previously reimbursed for vehicle oil consumption tests;
  • Cash reimbursement for expenses not previously reimbursed for vehicle repairs to address oil consumption;
  • Cash reimbursement for certain engine oil purchases, to the extent not previously reimbursed;
  • Extended Power train Limited Warranty to cover authorized repairs to correct excess oil consumption (up to the earlier of 8 years or 100,000 miles);
  • Cash reimbursement for rental car expenses and towing fees for the period of time the vehicle was being serviced for excess oil consumption.

What vehicles are involved?

Remedies are only available for people who bought or leased one of the following vehicles within the continental United States (including Alaska):

Automatic/CVT Transmission Manual Transmission
2011-2014 Forester (below VIN *529004) 2011-2015 Forester (below VIN *543624)
2012-2013 Impreza 4-door (below VIN *033336) 2012-2015 Impreza (below VIN *270253)
2012-2013 Impreza 5-door wagon (below VIN *886714) 2013-2015 Crosstrek (below VIN *2702874)
2013 Crosstrek (below VIN *856139) 2013-2014 Legacy (all)
2013 Legacy (below VIN *048086) 2013-2014 Outback (all)
2013 Outback (below VIN *321435)

For more information, including the proposed settlement agreement, the claim form, important dates, and answers to frequently asked questions, visit the lawsuit settlement page at http://www.oilconsumption.settlementclass.com/index.html.

Autolite 1 Barrel Accelerator Pump Action

Accelerating Pump System

Smooth acceleration requires a momentary increase in the supply of fuel. The air flow through the carburetor responds almost immediately to any increase in carburetor throttle valve opening. The fuel within the metering passages will lag momentarily in its response to the pressure difference created by this increased air flow. This lag in fuel response will cause a temporary leanness in the fuel air mixture that results in a hesitation in engine acceleration. A mechanically operated accelerating pump system supplies added fuel to provide a richer fuel air mixture for this brief period of time.

The accelerating pump, located on the side of the lower body assembly, is actuated by linkage connected to the throttle shaft. When the throttle is opened on acceleration, the diaphragm forces fuel from the accelerating pump chamber into the discharge channel. The inlet ball check closes to prevent a reverse flow of fuel. Fuel under pressure forces the discharge ball check and the weight off its seat, allowing fuel to pass up to the discharge nozzle. The fuel is sprayed from the nozzle into the air stream above the main venturi.

When the throttle plate is closed on deceleration, a return spring forces the diaphragm back, drawing fuel through the inlet channel. The inlet ball check opens, allowing fuel to pass into the chamber while the discharge ball check closes, preventing entry of air.

Watch a video about how the accelerator pump works:

Holley 1940 Float

The Holley 1940 carburetor originally used a Nitropyl type of float and because they tend to absorb fuel over time, we recommend that they be replaced at each carburetor rebuild. Once a Nitrophyl float has absorbed fuel it will become too heavy and allow more fuel to enter the bowl than what is needed, causing a flooding effect.

1940 Float

The only way to test the Nitrohyl float is to weigh it. The 1940 float should be 12.0 grams. If you don’t have a scale, then replace it.

The Nitrophyl float can be identified by the black color and it looks like it is made of a plastic material.

The Nitrophyl float has been replaced by a brass type. The brass float is tested by heating up a pan of water just prior to boiling, immerse the float, look for any bubbles.
1940 Float

Why the Tucker Was “The Car of Tomorrow”

The Reason Why the Tucker Was “The Car of Tomorrow”
It’s sad to see great ideas suddenly coming to a sudden death due to different political, economic or financial issues. While our free world tends to believe everyone should be able to pursue their dream, this isn’t always the case. A good example for such a sad scenario was Preston Tucker, the designer and developer of Tucker automobiles.
How it all started

Since the Second World War was over, the globe was ready for a change, for new developments and out of the box thinking. Everyone in the US was waiting for new vehicles to buy; however none of the three leading automakers did something to fulfill the ongoing demand.
The newest vehicle someone could own at that particular moment was at least 7 years old, as nothing new was produced since 1941.
This particular idea crisis led to the growth of smaller automakers which, although were working on providing new models, many of the features were still inspired from the already existing products. This is where Preston Tucker had the advantage, as he designed a vehicle with a design out of its time.
A completely new car

Tucker brought up a car concept built from scratch. It included a flat-6 cylinder rear mounted engine, rear wheel drive and independent suspension. Some of these features may actually sound as being contemporary, but this was all happening almost 60 years ago.
For safety purposes, a perimeter frame surrounds the whole vehicle in order to absorb crash forces and a roll bar was included discreetly in the roof. The steering box is strategically positioned behind the front axle of Tucker, to protect the driver in case of an accident.
Windshield and windows were made from shatter-proof glass designed to be easily removed in case of an unfortunate accident, facilitating the emergency exit of the driver and passengers.
When saying that Tucker 48 was a new car, it is not only about the new features included in the limited 51 piece series. 1948_Tucker_Sedan_at_the_Blackhawk_MuseumIn fact, every car was different from the one before and the one going to be built after her. Preston Tucker improvised on the move, adding and testing new concepts as Tucker 48 vehicles were rolled out the factory.
The uncover of the first Tucker 48 prototype in Chicago back in 1947 was doomed in front of over 3000 people as various issues popped up in the last minute and couldn’t be fixed in time for presentation. Among these, suspension arms popped under the heavy weight of the vehicle, the engine was incredibly loud and only developed around 80hp of the promised 150.
Although the original torque converting gearbox mounted on the first Tucker 48 prototype had no mean of going in reverse, Preston Tucker followed his intent of building a new transmission system. With help from Warren Rice, the inventor of Buick Dynaflow, the Tuckermatic was invented. It consisted of just 27 parts, double torque converters reducing everything to just one forward and one reverse gear. Three versions of the Tuckermatic were built: R1, R2 and R3. The first one never saw its way onto an engine as it required the motor to be turned off in order to switch gears.
The fall
Since the need of capital was constantly increasing as Tucker 48 was moving on with development, Preston Tucker started selling Tucker 48 accessories through his Tucker Accessories Program even before the vehicle was finished. This caused an investigation by U.S. Securities and Exchange Commission and the United States Attorney.
Although charges were eventually dropped, there was enough negative publicity to drown Preston Tucker’s project and cause only 51 Tucker automobiles to see the light of day. Fortunately, many of them are still in great condition and can be seen in various auto shows.

Route 66

Like an elegant actress in her senior years, Route 66 is an institution, a collection of fond memories, and a valued piece of Americana. While the highway number has been decommissioned and alternate route choices are abundant, much of the earlier roadway remains in use. The road spanned eight sates, which may not sound like a lot if you are thinking about states along the East Coast. But it becomes a lot more impressive when that 8-state drive is a whopping 2,450 miles. Today’s I-95 traversing the entire length of the Eastern Seaboard stretches only a bit more than 1,900 miles, running through 15 states and Washington, D.C.

Route 66 is an almost archetypal institution in American history due to its function as the original paved road from the Great Lakes region to the West Coast. Timing was also a major factor in the fame and function of Route 66, as it came into existence in time to meet the challenge of the Great Depression, with many travelers seeking better opportunity “out west.” But this road has an even earlier history, before it became known as Route 66, the “Mother Road,” or “Main Street of America.” Earlier, much of it had been known as the Old Trails Road, and some of it even followed pre-existing Indian trails. But none of its earliest history foreshadowed the greatness that was to become known as Route 66.

U.S. Route 66 was officially established in 1926, but the entire length stretching from Chicago to Los Angeles was not fully paved until the late 1930s. That was just before American novelist John Steinbeck popularized it in The Grapes of Wrath, as “The Mother Road” in 1939. Even the paving of this iconic road was a story in itself. The Depression created a massive unemployed work force, which completed the construction in a major government initiative creating needed jobs.

Popular Culture

After both the novel and the film titled The Grapes of Wrath created the public awareness of Route 66 as The Mother Road, the highway was further popularized by the highly successful pop song, “Get Your Kicks on Route 66” in 1946, and the iconic “Route 66” TV series debuting in 1960. The series highlighted seemingly continuous travel on the highway by two young men in a Chevrolet Corvette. The popularity of the TV series may also have been in part responsible for the many re-recordings of the original Nat King Cole song. In any case, the highway has become almost synonymous with leisurely episodic travel in the United States despite the growth of the Interstate Highway system, which was supposed to revolutionize road travel, replacing the need for such “outdated” routes.

The most recent popular surge in the mystique of Route 66 came from the Pixar Animation film, Cars, which details the adventure of several characters in the context of a fictional town, victimized by the construction of the Interstate highway system’s redirection of traffic away from small towns along what is conceived to be Route 66. The movie, Cars, debuted in 2006, and has been followed by two more feature length films, two TV series, and a short film, as well as nine video games, extending the Pixar franchise into 2016 (3rd film’s release). A major factor in the popularity of Cars is its use of references to actual places and structures along Route 66, and featuring the fictional town (Radiator Springs) that imitates both the name and location of a real town (Peach Springs) and implicates many actual settings along the highway.

The Interstate Effect

The film, Cars, accurately depicts the effect that I-40 had on towns along old Route 66, as almost overnight it transformed popular stopping places along a major highway into near ghost towns. Much of the growth that had blossomed along the highway faded into history. Businesses and whole communities died.

It was in 1956 that Congress passed the Federal Aid Highway Act authorizing the construction of the national interstate highway system. While the system as a whole took many years to develop, as each section of Interstate was completed the older routes it replaced suffered immediate consequences. And by 1970, almost all of old Route 66 was bypassed by modern four-lane divided highways. Falling into disuse and disrepair, Route 66 was decommissioned in 1985. But by that time the song, the TV series, and the reality of the nostalgia had already lighted an indestructible fire in the imaginations of Americans. Route 66 simply refuses to be destroyed.

However, not all communities have survived. Even some other industries have reshuffled because of the changes. The auto industry is no exception, with many previous manufacturing plants having relocated. Chicago retains only a shadow of its former contribution to the auto industry, with Ford manufacturing only the Explorer, Taurus, and Lincoln MKS in the Windy City. Today, only General Motors still manufactures vehicles in the St. Louis area. They make the GMC Canyon and Chevrolet Colorado trucks and Chevy Express and GMC Savana vans in the nearby Wentzville plant.

But today organizations and communities have re-energized many parts of the old girl with restoration projects and promotion of her sights, sounds, and memorabilia.

Points of Interest

Hundreds of interesting points remain along this nostalgic path captivating Americans yearning for a connection to the past. Some are thriving businesses, living off of the continuing attraction this highway brings to their door. Others are actual (or practical) ghost towns. One of the more notable communities that now exist primarily as reminders of what used to be, is Texola, Oklahoma. Perhaps one of the most ironically named establishments there, is the Last Stop bar. It is perhaps the only business that remains in operation in the community. Indeed, it is a last stop in several ways.

Never a large community, Texola’s largest census population figure was 581 in 1930. Even during the prime years for Route 66, the town suffered a declining population. Today, there are supposed to be 36 residents, but finding a live person or moving vehicle there is a challenge. Abandoned buildings can be entered at a tourist’s leisure. In 1995, the National Register of Historic Places included in its listings the town’s Magnolia Service Station.

In the movie, Cars, the Cozy Cone Motel is taken from the design of two remaining Wigwam Motels in Holbrook, AZ, and Rialto, CA. Even the name is a reference to another site along Route 66, the Cozy Dog Drive-in in Springfield, IL.

Many museums, gift shops, and memorabilia vendors have grown quite successful along Route 66. One such stop worth noting is the Route 66 Hall of Fame and Museum in Pontiac IL.

At the road’s eastern-most end, a sign post in Chicago beckons the traveler with this message:  “Begin Historic Route: Illinois U.S. 66.” Many maps and books are available to prepare an itinerary for a thorough trip down this historic memory lane. It is well worth the trip, and preparation is a good idea.

A big part of the charm that continues to attract travelers to the quaint and slower-paced scenic route 66 is the fact that it is reminiscent of times gone by, where we lived at a slower pace, with less distraction and more wholesome enjoyment of life. Think of it as a highway connecting you to places a little like Andy Griffith’s Mayberry.

The continuing popular nostalgia of traveling Route 66 is proof that the Interstate has not and apparently cannot kill this proud old matron of travel. If the Interstate is more like actress Kim Kardashian, then Route 66 is our genuine and highly respected Betty White. It is no coincidence that another of the names for this old road is “Will Rogers Highway,” in recognition of another of America’s most cherished figures.

Carter Thermoquad

Throughout the 1970s and early 80s, the Carter Thermoquad (TQ) was a popular carburetor found on many Chrysler products as standard equipment, and on some Ford Motor Company vehicles, as well. The earliest version was in the Competition Series first released in 1969. Production versions followed in 1971 on Chrysler’s 340 c.i. engine. The TQ was discontinued briefly in the mid 70s, then reintroduced as the 9000 series for its final production years.

The Thermoquad was a large four barrel configuraton, with what was called the spreadbore design, two smaller primaries for fuel economy and two large secondaries. When those secondaries kicked in, you knew it. It came standard on many Chrysler engines including the big 440 c.i. mill, most 360s and even on many 318s. International Harvester used the TQ sporadically on its 345 and 392 engines. The big Lincoln 460 c.i. engine occasionally sported the TQ.

A quite distinctive touch on this carburetor was the material of which the main body was constructed. Between the lower throttle flange below and the aluminum bowl cover above, this black phenolic plastic section was designed to provide a cooler operating environment for the gasoline in the float bowl. It worked to effectively lower the operating temperature by about 20 degrees. And this plastic resin main body, then, is what gave the thermoquad its name.

The TQ was a dual bowl carburetor with the bowls housed in the phenolic plastic body. Each bowl served half of the carburetor: one primary and its related secondary. The first thermoquads employed brass floats while the later versions after 1973 were all nitrophyl floats.

The spreadbore design feature was shared in common with other carburetors, even those from other manufacturers, including popular Rochester and Holley designs that shared a common flange connection with the Thermoquad. Therefore many of these carburetors can be swapped out with the right adapter.

The original factory Competition Series of the TQ came in two flow ratings, 850 and 1,000 cfm. Production versions ranged from 750 to 850 cfm. This carburetor was also produced in aftermarket versions rated up to 1000 cfm.

Produced over such a long lifespan, the TQ came in literally dozens of versions, and many parts are not interchangeable from one version to the next. Correct identification of which version your engine carries is therefore critical. There are many different numbers found on the carburetor, but most of them are casting numbers. The actual model number is stamped into the lower left bolt flange at the rear of the carburetor. Some early versions also had a tag displaying the model number attached to one of the mounting bolts. Some later versions also included a bar code sticker identifying the version. Some rebuild kits and all nitrophyl floats remain available.

Buy Thermoquad Carbuetor Kits


Floats perform an important function in maintaining the correct level of fuel in the float bowl by opening and closing an internal inlet valve. If the float develops a leak, it will sink below its ideal level and excess fuel will enter the bowl. This causes the engine to run rich and probably causes leakage of gasoline out of the carburetor, increasing the risk of engine fires. In a carburetor rebuild be certain to examine the old float for damage or corrosion. You can also test your float for leakage to determine if it needs to be replaced. Repairing old floats is difficult, especially in light of the need to avoid increasing the weight of the float with the addition of solder. Adding weight changes the floatation characteristics of the float.

We have one of the Internet’s widest selections of floats including all floats that remain available and many that are extremely hard to find. We have floats for all of the major name brands of carburetors. These floats are made in the U.S.A. and designed and built to the highest quality standards, including both brass and nitrophyl floats. In some applications, both are available to choose between. We do recommend changing all old nitrophyl floats at the time of a carburetor rebuild, and many mechanics change all floats during rebuilds.

From Holley, Carter, and Motorcraft to Stromberg and Zenith floats, we have them all, including a wide selection of Rochester and Marvel Schebler floats. If it is time for a float replacement in your classic car, scroll our selection and find your carburetor float at a price that will make you smile.

Float Problems and Their Diagnosis:

With brass floats, the floating “pontoon” is typically constructed of at least two brass sections soldered together along a seam. Then a tiny hole used to equalize internal and external temperatures is soldered shut to complete the assembly process. Since all of these points are submerged in gasoline during engine operation, leakage problems can later occur at any place that was soldered. Repairing these floats is quite challenging and replacement is usually preferred unless the float is no longer available.

If your engine is the least bit hard starting after it has warmed up, or if your exhaust has a rich gasoline odor, you probably have carburetor problems, and a bad float is one of the possibilities. Other symptoms include poor gas mileage and, of course, if the engine is flooding.

Is Ethanol Good for my Car?

Classic cars are not the best match for today’s ethanol enhanced gasoline. If you use it in many of the older models, be prepared for earlier component failures. Most automotive parts wear out over time, but ethanol speeds up the deterioration of many, especially those made of rubber or cork.

Older cars with rubber fuel lines are especially vulnerable. A failed rubber fuel line can result in an engine fire. Who needs that? But the fuel line constitutes the most easily addressed area of concern. Other components that are frequently damaged by ethanol include carburetor float valves, rubber accelerator pumps, pump diaphragms and die-cast carburetor bodies, rubber fuel pump diaphragms, galvanized fuel lines and fuel tanks, and gaskets made of either cork or rubber.

Because of its deleterious effects, ethanol rated as E85 (which is only 15 percent gasoline and 85 percent ethanol) should be avoided at all costs. But even the smaller 10 percent ethanol rated E10 will deteriorate components far faster than pure gasoline. Ethanol also attracts moisture, so use a quality fuel stabilizer to help control water retention.

Of course, if you can avoid ethanol altogether, that is your best option. Today there are not many places where you can get ethanol-free gas, but it behooves you to look for them. If you are lucky enough to have a local supplier, seize the opportunity for your car’s sake.

If ethanol cannot be avoided, then make regular fuel system inspections your new standard operating procedure. If your car does not have to retain its stock condition, it is a good idea to install an inline fuel filter so inspection of your gas is easier. Monitor this and the fuel bowl for traces of cork or rubber. If you see either, you already have trouble.

Also inspect the carburetor, both internally and externally. Look for signs of fuel leaks or residue of cork or rubber in the fuel. Check for loosened bolts from weakening gaskets. Check the needle valve. Its replacement may be required much more frequently than in the old days.

Unless the car is driven quite infrequently, regular monthly inspections of your fuel system should be performed and rubber components should be considered for replacement annually.

Of course, if your classic does not have to remain stock, your options increase dramatically. There are now stainless steel fuel tanks available, as well as stainless fuel lines, and they are completely trouble-free in relation to ethanol. There are also replacement carburetors that are impervious to ethanol problems, so if you drive a car that does not have to remain original, these replacements should solve your fuel-related problems for good.

Ethanol and classic cars are not good bedfellows. But a careful regular inspection regimen and timely replacement of key parts can make the relationship at least livable.

Adjusting the Idle Mixture

The Carburetor Idle Circuit and Adjusting the Idle Mixture

The idle circuit is in effect only when idling. Once RPM increases above idle, the Idle mixture screws are no longer in play. If you have the idle RPM set too high, your idle mixture adjustment will be irrelevant. When you turn the idle mixture screw in all the way and the engine doesn’t change, you could have the idle RPM set too high. For example if it was at 1,000 RPM. On the other hand if the idle is normal, then you have a problem in the carburetor, or possibly a vacuum leak.

The idle mixture screws sets the mixture of fuel and air during idle RPM.

Single barrel carburetors will have one idle mixture screw while 2 barrel and 4 barrel usually have 2 idle mixture screws.
You can clean your idle mixture screws by buffing them off with a wire wheel.
Inspect the screw for grooves. Grooves are created when the screw is turned in too tight. Replace any damaged or bent screw.
Inspect the screw hole to make sure it is clear. When you blow through the hole you should get air inside the bore.

For Rochester Quadrajets pick up a idle mixture adjusting tool at most any part store. The tool bends which will make adjusting easier.

When assembling the carburetor turn the idle mixture screws in all the way, gently seat, then turn it out about 1 1/2 turns.

Bring the engine up to operating temperature.
Make sure the choke valve is completely open.
You may have to rev the engine slightly so that the fast idle cam moves to the idle position.
Adjust the idle to specification.

There are a couple of ways to adjust the idle mixture.

1. Using a vacuum meter
Hook the vacuum meter to one of the vacuum ports on the intake, or the carburetor.
Take turns with each idle mixture screw.
Turn each screw out a bit for a start (maybe 1 turn).
Turn each screw in 1/4 of a turn and wait for a second for the vacuum meter to catch up.
Do this until you get the smoothest idle and the vacuum meter stays steady.

2. By ear
Take turns with each idle mixture screw.
Turn the screw out 1 turn to start.
Turn the screw in 1/4 and wait for a second for the engine to catch up.
Keep doing this until the RPM starts to drop.
Turn the screw back 1/4 – 1/2 turn.