Advanced Valve Train Technology For Kart & Jr. Dragster Racing If you have any questions concerning installation or proper use of your new Go-Parts™ products, call us toll-free at 1-800-976-9376. The following instructions are designed to help you determine the existence of excessive pressure loss from your single cylinder small engine.Make sure the flywheel is secured!Go-Parts™ Leakdown Test For Briggs & Stratton™ 5 HP EnginesCAUTION: Pressurizing the piston cylinder can force the piston down VERY quickly if the flywheel is not secured. Severe injury can occur during leakdown tests if you do not secure the flywheel properly. Make sure the flywheel can not turn!Note: Remember that your goal is a hi-performance racing engine, it is in your best interest to follow these instructions. By not following these simple steps, you may reduce horsepower, efficiency, and the performance of your engine.Note: You can not check for pressure loss without a source of compressed air (100 psi) or a leakdown tester. This dual gauge leakdown tester allows you to regulate the incoming supply pressure and the cylinder pressure at the same time.Mount the engine to your kart frame or a sturdy bench that you can start and run the motor on.Start the engine and run at idle for about five minutes or until the head temperature is around 200 degrees.Remove the blower housing and spark plug. Rotate the flywheel until the piston is at TDC and both valves are closed, lock the flywheel so that the engine can not turn. CAUTION: Pay great attention to locking the engine at TDC. When you pressurize the cylinder, the piston WILL move down in the cylinder causing the exposed flywheel to rotate very quickly in either direction if not securely fixed in position. Personal injury can occur. Connect a pressurized air supply hose (from your air compressor or air tank) to the regulator portion of the leak down tester . Open the compressed air regulator until the pressure gauge reads 100 psi. Screw test hose into the spark plug hole of the engine. You are now ready to pressurize the cylinder.Make sure the flywheel is secure. Using the quick-connect on the test hose, attach it to the leak down tester, this will pressurize the cylinder. Check that your regulator gauge still reads 100 psi and adjust if not.Subtract the cylinder pressure from 100. This is the percentage of leakage in your engine. A 2% leakage (98 using 100psi) is about the best that you can expect.Excessive leakage can usually be heard at rings, valves, gaskets, or cracks in anything. Check your installation and condition of these parts and correct if necessary.If you can't get the correct results, call us toll-free at 1-800-976-9376 for assistance.