Pmo Carburetor Manual' title='Pmo Carburetor Manual' />Porsche 9. Carburetor Adjustment, Balance and Tuning 9. Cataloging Single Issue Serial. This article is one in a series that have been released in conjunction with Waynes book, 1. Projects for Your Porsche 9. The book contains 2. With more than 6. Porsche 9. 11 owners collection. See The Official Book Website for more details. Well adjusted carburetors are key to good engine performance. If your carbs are unbalanced, then different cylinders in your engine will receive different amounts of fuel and air, and the all important airfuel mixture ratio will be off. This will result in less horsepower, a poor idle, and higher emissions. Its a wise idea to check the balance of the carburetors each time that you perform a major tune up on your engine. The most popular system for use on the 9. Weber triple throat carburetors. The remainder of this project will discuss the procedure used for balancing a 9. Weber carburetors. If your carburetors are poorly balanced, then you will have a multitude of problems with your engine. The engine will have a tendency to spit and backfire through the exhaust. Pmo Carburetor Manual' title='Pmo Carburetor Manual' />Unbalanced carbs may also give the engine an uneven idle, or make the car very difficult to keep at idle without stalling. Its important to make sure that your engine is in good overall health good compression, and that your idle jets are clean as well. Dirt in the idle jets, poorly adjusted valves or a burnt exhaust valve can also result in the same symptoms that are associated with unbalanced carburetors. The first step in adjusting your carburetors is to make sure that the rest of your car is tuned and performing properly. Make sure that your valves are properly adjusted Pelican Technical Article Valve Adjustment, and the timing and dwell are set properly Pelican Technical Article Setting the Timing, Dwell, and Idle Speed. Ping Eye 2 No Serial Numbers on this page. Make sure that your spark plug wires are in good condition, your plugs are new, the carburetor floats are properly adjusted Pelican Technical Article Carburetor Rebuild, and the idle jets are clean. Let the car warm up to its normal operating temperature before starting to adjust the carburetors. Pmo Carburetor Manual' title='Pmo Carburetor Manual' />Once the car is warm, begin by adjusting the idle to about 1. RPM. You want to set the idle to be a little bit higher so that the car will not die out when you are making adjustments. Adjust the engine to this value by carefully turning the idle adjustment screws located on the ends of the carburetors. Now, remove the air cleaner from the top of the carburetors. The stock air cleaner is simply clipped onto the top of the engine, and can easily be removed. If you have an aftermarket filter assembly, you can remove these by simply unbolting the air cleaner housing on each carburetor. Now, disconnect one of the two small drop links on the throttle linkages so that there is no connection between either of the two carburetors. Once you are sure that the timing is set correctly, and the idle speed is set to your working range of 1. Pmo Carburetor Manual' title='Pmo Carburetor Manual' />Enter Model Number Model Manual Parts Diagram NEW CX1400 49STCSA PC0141400 Manual NA. CARBURETOR INSPECTION AND INSTALLATION. Webers is not needed with the PMO carbs. Care must be taken. PMO CARBURETOR ADJUSTMENT. RPM, its time to synchronize each of the carburetor throats. A special synchronization tool sometimes called a Unisyn or synchrometer is used to measure the air flow being sucked into the manifold by each carburetor throat. The goal of the synchronization task is to make sure that the amount of air flow into each throat is the same for all six cylinders. 101 Tricks With A Thumb Tip Pdf Software there. Start with cylinder number one, located on the rear left side of the engine. Place the synchronizer over the top of the carburetor stack and adjust the tall glass stack to a vertical position. Turn the adjusting disc on the synchronizer until the small indicator bubble inside the glass rises about half way up the height of the synchronizer. This basically calibrates the synchronizer tool for cylinder one. Now, place the Unisyn on one of the throats of the right bank of cylinders. Adjust the idle adjustment screw located at the end of the carburetor until the ball in the Unisyn is at about the same height as it was on cylinder one. The idle speed should either rise or drop off a bit from the level that you had it set at. Starting with cylinder number one, adjust the mixture adjustment screw at the base of the carburetor. On each Weber carburetor, there are three mixture adjustment screws that have a spring wrapped around the inside to prevent them from turning. Turn this screw in until the idle begins to drop. Then back off the screw about an 18th of a turn or until the idle comes back to its previous level. The goal is to turn in all the mixture adjustment screws right to the point where they begin to affect the idle. Repeat this procedure for each cylinder on each side of the car. If your mixture adjustment screws are turned in too far, then you will be starving your engine of air. This will result in a popping type backfire out of the exhaust. When all the mixture adjustment screws have been set, then readjust the idle adjustment screws located on each end of the carburetor until the idle is adjusted back to 1. RPM. Use the Unisyn to make sure that both banks of carburetors are drawing the same amount of air while the car is at 1. RPM. Next, take the Unisyn and measure the level of air flow that each cylinder is drawing through the carburetor. Make a note of the level of the highest cylinder you will adjust all the other carburetors to level of this cylinder. There are three air correction screws that are located at the base of the carburetors and have a small nut that locks them down to prevent them from rotating. Adjust the air correction screws so that the level of each cylinder as shown by the Unisyn is equal to the reading on the highest level cylinder. Adjusting the carburetors in this fashion will give the car a strong idle and make it run very even. If for some reason, you cannot adjust all the cylinders to the reading on the highest cylinder, then adjust that one down slightly to the point where all the cylinders can be synchronized together. After adjusting all the air correction screws, reset the idle back to the 1. RPM range, using the Unisyn to verify that both sides are evenly balanced. Once all the cylinders are set and synchronized, its time to adjust your linkage. The accelerator linkage must open each carburetor by the same amount at the same time. In other words, both the left and right carburetor linkage must be synchronized with each other as the throttle is depressed. First, carefully inspect your throttle linkage. All of the links and ball joints should be tight and have almost no slop or backlash. If there is significant wear on these joints, then they should be replaced, as you will find it very difficult to adjust the linkage and balance the carburetors. To adjust the linkage, you will need to change the length of the linkage arms by rotating the ball joints at the ends of the arms. The linkage has two drop links, whose length controls when the throttle bodies are opened and closed. If the one carburetor opens earlier than the other carburetor, then you need to decrease the length of the throttle linkage drop link until they both open at the same time. The drop links are threaded with both a left and right handed thread similar to the tie rods, so you can get a very fine adjustment simply by rotating the drop link in either direction. Tighten up the retaining nuts on each end of the drop link when you have finished adjusting the linkage. In addition to checking both the idle mixture and the linkage, you should also check the adjustment of the accelerator pumps.