A compression test is a dynamic test engine moving a cylinder leakdown test is a static test engine at rest. The internal fuel tank and cover plate are removed to expose t he flywheel.
Outboard Compression Testing
Outboard leak down test. The second gauge will show you how much pressure has been lost. The first is called a leak down test. In this video i show how to perform a leak down test on the yamaha 50hp outboard motor. The gauge measures the amount of air getting past the rings valves or other passages and provides a reading compared with zero leakage. There are two basic ways to compression test an outboard. Heres a step by step breakdown of the test.
This uses a special set of gauges. A leak down test is performed with the engine not cranking. So far it is looking like there is a burnt out exhaust valve on cylinder one and maybe two but well find. In a cylinder leak down test the engine is placed on tdc of the cylinder in question. Dangar marine 24480 views. Performing a leak down test on an outboard marine engine duration.
In contrast to the cylinder leak down test which measures how much pressure is lost in the engine. Use the leak down test to know if you should be changing head gaskets valves piston rings or looking for a crack. One gauge will tell you the pressure of the air compressing the cylinder. The spark plug is removed. So the compression test measures how much pressure the engine can produce while cranking. Simply put each piston is placed at top dead center and the cylinder is pressurized through the spark plug hole with the leak down tester.
If the compression is low in a cylinder its time to find out why. The leakdown gauge is hooked up to the compressed. To perform a leak down test you would pressurize the cylinder with compressed air. Performing a leak down test on the yamaha 50hp outboard motor. Fuel additive first the engine should be warmed to operating temperature providing it still runs.
Gallery of Outboard Leak Down Test
