I would do a leak down test before you start changing things. First, you don't know what cylinder to zero in on, then you don't know the issue that the cylinder has. A leak down test will find the cylinder in question and the problem much quicker than fiddling with every cylinder checking 'everything'.
http://www.harborfreight.com/cylinder-leak-down-tester-94190.htmlIf you do use it, the instructions are wrong.. do it this way:
This unit works perfectly fine. What ollie says it correct.
First install the adapter hose into the cylinder to test and be sure that cylinder is at TDC of the compression stroke.
Turn the regulator fully counter clockwise, then hook up air hose to the tester (no higher than 100 psi so set this on your air compressors regulator, can be 30-100 psi)
Then turn regulator clockwise until the needle aligns at zero.
Then (and only then) hook up the leakdown tester to the adapter hose that you screwed into the spark plug hole earlier.
Read leakdown percentage and listen at the stated locations to diagnose.
The instructions say to hook up the leakdown unit to the adapter hose first, before setting needle at zero, etc. This doesn't work, but was obvious to me. It's just a typo. Nothing wrong with the tool
