how to check compression?

[bluebrownie]

can someone share with me the process for checking compression in my cylindars... i have the guages...never done it before... want to make sure i do it right...tx

 

[ezeke]

Re: how to check compression?

All spark plugs out. Pull the emergency lanyard to suppress fire. Engine should be warmed if possible. Be as consistent as possible and use a fully charged battery.

If the engine is a carbureted four stroke, open the throttles.

Be sure to write down the results for later comparison.

 

[F_R]

Re: how to check compression?

As ezeke said. If I may add...
If you don't have a lanyard, ground the spark plug wires.
Cold engine or warm...different results may be obtained. Part of the evaluation process.
Open the throttles on a four stroke. Not necessary on a two-stroke, but to avoid an arguement go ahead and do it if you want. Won't make any difference though.
Crank the motor till the gauge won't go any higher. That will be the compresion pressure. Normally around five revolutions.

EDIT: Adding oil to the cylinders is cheating and gives false readings.