Check them before the carb is installed. The typical symptom on a book-value Weber conversion is a bog unless you baby the throttle. You are done with that cylinder. It may seem counterintuitive, but too much fuel in the pump shot can actually result in a lean condition. On carbs with the cold-start controls interconnected, those clamp screws should also be released. . This is a particularly valuable tool for cars that get track use so that you make sure you do not lean out and put a hole in a piston.
The camshaft that I selected was manufactured specifically for Webers and is available through the Inglese division of Comp. For street use, however, we want our engines to idle nicely, and to perform well throughout the throttle range — not just at small and large throttle openings. The bores that the assemblies sit in are open on the bottom to the float bowl. As long as the engine stays running idle speed is not important at this point. Once you feel like you have the 3rd gear conditions properly tuned, try 2nd gear again and make sure it still works well. In the case of the emulsion tube, there are really only a few which work really well for V8 applications; and if you aren't using one of them it is certainly a big part of the problem. Move on to the next cylinder.
See our Ignition tech page for more details. Make sure the linkage is symmetrical. The weiners were offline for a spell. Start with the screw or screws out 1. Below are steps for synchronizing carbs if anyone is in interested. Increase the size of the idle air jet hole.
I made a gauge that is 5. As with a lot of things on vintage cars, the looks and noise are half the draw. The concept actually ends up being quite simple, even though the math and science behind the concept can be exceedingly complex. This is the surrogate for the needle valve, and I made one out a piece of aluminum and a machine screw: It screws into the carb body using the carbtop screws and acts like the needle valve by limiting the travel of the float. This is a very volatile substance that is easily sucked into a leak and causes a dramatic change in engine running condition… With the car at idle spray carefully around the base of the carb or throttle body, at the area where the manifold meets the head, around vacuum hoses and any connections either below the carb base or after the Mass Air or Air Flow Meters…Any noticeable change in idle speed or quality will indicate a vacuum leak How Do I get rid of it when I find it? When doing multiple carburetors all linkage should be disconnected. Now both mixture screws need to be set the same. Every engine responds differently, and final jetting changes are most often determined by the engine builder or tuner.
Realize that as the engine warms up the geometry changes slightly so there may be some difference between hot and cold engine. Start engine as long as engine starts and runs do not turn up idle speed first. When you get to this point that cylinder is too lean. Emulsion tubes complete with main jets and air corrector jets 64. Check that the fast-idel-screw photo 6 on each throttle lever some have only one is clear of the cam that operates them, so that there is no danger of them interfering with the setting of the slow-running.
This is because the mixture leans out when you try to suddenly involve the main jets with insufficient airflow. Changing flow through the idle fuel jet and idle air holes will thus most significantly change cruise mileage. To confirm settings with the engine running. Now unscrew each one by an equal amount, say two turns. If the drag of the throttle cable and pedal slow down the closing action of the linkage, install two helper throttle return springs. The throttle shaft rides in a set of precision roller bearings.
In order for the reaction to be stoichiometric, there must be two hydrogen atoms for every oxygen atom. Now turn to the throttle stop screw B on the other carburettor and unscrew this until it is quite clear of the throttle lever and thus that carburettor is fully closed. Do not use high pressure air to blow dry. As always, consult the owner's manual or shop guide for your make and model, if you can't find the screws. The fuel line can now be installed. A false reading will be obtained if the lid is held horizontally.
Ignition Systems, Spark Output and Spark Advance: This is a serious topic that seems to get ignored even by professional installers. If this cannot be done you will need to recheck bench assembly for binding throttle in high flow Carburetor. If it will not start as it is, open up each throttle by the same amount, till it will start and run at a reasonable speed. This is sometimes a tricky area, because the first thing you want to do is throw in a bigger idle jet, but sometimes playing with air bleeds, mixture screws, or choke sizes can accomplish the same thing while sticking with the original jet size. Check that the choke cable is allowing the enrichment levers on the back of the Webers return to their stops. Both of these are located under the the float bowl lid, which covers the top of the entire carburetor body.
I have the distributor curved to bring another 20 degrees of advance in by 2000 rpm for a total advance of 38 degrees. White is too lean, and black is too rich. That's another topic, but about 0. You need to find what is right for that particular engine. The new throttle arms should now be put on. As has already been mentioned, this tool measures the height of the needle valve over the underside of the top section of the carb.