Hello there
Testing your compression:
- TESTING PROCEDURE
1. Run the engine for about 5 minutes or 10 until it reaches normal operating temperature.
2. Stop the engine, disconnect all spark plug wires one at a time and label for proper reconnection.
3. Loosen all spark plugs about one turn, then if you have air hose use it to blow all the dirt out of the spark plugs, place them on a clean, flat surface in the order in wich they were removed, this will to correlate any compression problems with the conditions of the plug from the particular clyinder involved.
4. Screw the spark plug adaptor hose into the spark plug hole, hand tighten only, DO NOT USE A WRENCH.
6. Make sure your kill engine is off, hold the throttle and crack the engine or kick start it until pressure stops rising on the tester.
7. Record the compression reading and repeat the test on all remaining clyinders.
- TEST RESULTS
1. On a normal clyinder, the needle should advance on each stroke until it reaches a peak, all clyinders should test within the engine manufactures specifications and reading should not vary more than 10% from clyinder to clyinder.
2. IF the needle fails to advance normally or if it remains the same for several strokes and then start to climb, the clyinder has a sticky valve.
3. If the compression reading is considerably higher above the manuafactures specification, it is indicative or carbon build-up in the clyinder, use of spark plug with higher heat range can sometimes correct this fault.
4. If a reading on two adjacent clyinders is 20 pounds or more lower other clyinders, a defective head gasket is indicated, water and or oil may be seen in the two clyinders.