Compression test Vs Leakdown testing

ILENGINE

Lawn Pro
Joined
May 6, 2010
Threads
24
Messages
7,294
Was working on a small 1500 watt buffalo generator earlier today, and this highlights the inaccuracy of compression testing on compression release engines. Engine has been setting with stale fuel, so had to clean fuel system and carb to get it running. It now starts on the first pull.

Now for the test results. Leakdown test showed less than 10% leakage at TDC compression stroke but only has 5 psi on compression test.


We can also contrast that with a Briggs intek on I am also working on that has 60% leakdown with 130 psi compression. Engine was run with improperly installed air filter cover and is suffering from dirt ingestion damage and likes to fog the local mosquito population.
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
44
Messages
10,333
Definitely shows why compression tests have lost their importance in diagnostic tests. Also shows that when trying to diagnose problems your need to know what engine you are working on.
 
Top