Some people have asked questions, and I have spent several minutes composing an answer. Avoid using Teflon tape because threads from it can enter the fuel system and clog critical ports within the carburetor. This is why only computerized fuel injection systems can really hold anything close to 400mv. Master Spare Parts And Tech Guide. Put it all back together, check for leaks, then drive it until the engine is warm.
To the experts, this book is a valuable reference source for part numbers as well as clear and precise photos of parts and diagrams. A vacuum leak, if left unattended, causes the engine to run lean. Pop started me off rebuilding Ford Autolite carburetors, one of the simplest fuel mixers ever made. A mechanical oil pressure gauge should be connected even if this is to be temporary to verify oil pressure. Drill on the side opposite of the transfer slots, to help keep this added airflow away from the idle ports and transfer slots. Also, don't put the 50cc cam on small pump diaphragms! You will need to know the basics about how to work on your Holley, and a book or two will really help a bunch, because of the pictures and part numbers in them. Depending on other variables, such as vehicle weight and stall speed of an automatic transmission torque converter, moving to a smaller discharge nozzle may help the existing accelerator pump do its job.
The proper level of fuel is for the fuel to just touch the bottom of the sight hole without running out. You must use the big black cam on 50cc pumps to get the full shot of the 50cc pump! Please try to use some punctuation, and break up your questions so I can answer them easily. In order to get good readings, you will need to drive at a constant speed of 45-55 mph, accelerate lightly, and accelerate heavily. On the left is the ball and bail, on the right is the umbrella valve, uninstalled on that bowl to show the smooth sealing surface. If you, or a spotter, can see puffs of black smoke when the secondaries open, then it's too rich.
This amount may be all you have to spend, depending on what tools and instruments you have in your garage right now. Remember, your eyes are using this data, and if it stops for a while, no harm is done! There is a reason that the 0-4776 through 0-4781 double pumpers get bad gas mileage. Clear step-by-step illustrations and tips for performance, racing, economy, improved reliability, and even custom finishes for a show-winning appearance. Lube the pilot and pull gently through to the other side until you feel a light snap as the knob comes through. Common Problems Lots of folks have been emailing me with some common problems, so here are some tips for fixing these common problems.
This can easily create a splayed condition. Nozzle size only affects the duration of the pump shot. You must make sure that there is a clear path for the carb to draw a little bit of vacuum through the housing there is a small vacuum passage behind the housing , and that the air gets filtered somehow, either with an external filter, or through a hookup to the bottom of the air filter housing. Often, many enthusiast's first modification is swapping out the factory induction system for a new Holley 4-barrel carb and intake manifold. The Dominator flange is unique to the 4500 series. Which intake manifold should you choose? Exploded diagrams; cutaway flow diagrams; actual pictures; service tool summary; trouble shooting chart; step by step disassembly, reassembly, and adjustment procedures. The 4160 series is a slightly less-expensive variant of the 4150, featuring replaceable primary jets, but with a thin metering plate on the secondary side and no replaceable secondary jets.
I keep getting loads of emails from people who want me to answer questions that are already answered here, and they are even claiming to have read the page. Going up a slight incline at highway speeds, or accelerating slowly at highway speeds, you will notice the vacuum reading falling. A new carb will come with instructions, and a phone number to call if you have problems. These sensors are used in electronically fuel injected cars as a signal telling the computer whether to supply more or less fuel. Extremely informative, and suitable for framing if desired.
I can tell exactly which power valve I have in my car by the vacuum reading when the lean misfire goes away under light loads. This was a Holley school handout, and contains full page circuit diagrams of the various circuits. The most critical aspect, from a safety standpoint, is that there is no binding or sticking during any phase of throttle movement. And, if desired, you can move to advanced levels of tuning and modifying these carbs. Exploded diagrams; cutaway flow diagrams; actual pictures; service tool summary; trouble shooting chart; step by step disassembly, reassembly, and adjustment procedures. Also make sure that the carburetor mounting gasket clears the throttle plates. Organize your eBooks into a custom library and annotate pages.
Boats and other seasonal engines. Send me proof of no improvement, and the check is on the way. I know this from experience. All eBooks purchased from cartechbooks. You must download and install Adobe Digital Editions software on each device you plan to read from.
Below are part numbers and links to a common retailer, to which I am not affilliated. Floats: Most floats on Holleys are externally adjustable, except the Quadrajet replacement carbs, series 4175, most late-model smog carbs, and many marine carbs. The 3310-2 doesn't and it works ok. Open the secondaries a bit, and close the primaries a like amount. If using an open-end wrench, take your time and make sure that the wrench is fully and firmly seated on the fitting to avoid slipping and damaging the fitting. The rules didn't just happen overnight, nor were they something I wanted to do.
Here is a photo of 3 different vacuum secondary diaphragms. If you have problems with power valves blowing out, fix the problem, or install one of the available power valve protectors. The housing cover and spring simply pull out. Good carb for a warmed up 428? Individual velocity stacks provide isolated airflow paths for each carburetor. Check the clearance between the accelerator pump lever and the pump lever cam. Each circuit flows at different times, and some circuits flow even when you think they don't. Just make sure that it is not obstructed, including by other vehicles, so that the car can be pushed out if a fire gets out of hand.