Proper way to check compression ?

[Ironhorse2022]

What is the proper way to check compression on a 2 stroke ? I presume with a warm engine, crank 5 seconds, dry and wet (like a car engine) but don’t know for sure. Also, many used engines won’t or can’t be started so checking compression cold is the only option. How big an error will checking cold cause ? I searched this topic without luck. Thanks.

 

[racerone]

Normally done COLD !!----Plugs out.----Pull it over with a recoil till gauge stops going up.-----No need to open throttle on a 2 stroke.

 

[Ironhorse2022]

Perfect, thanks

 

[stresspoint]

the thing with compression testing is that it is only a comparison , test it any way that suits you but be consistent and have a full charged battery for each cylinder tested .

i like to test room temperature on all engines that way i know there is consistency in the test.

 

[jimmbo]

Ground the Spark Plug Wires, there a chance that some fuel vapour could be discharged from the Plug Holes and if there is a Spark

 

[Ironhorse2022]

Good points, thanks. A flame thrower would be unwelcome.

 

[so]

Ground the Spark Plug Wires, there a chance that some fuel vapour could be discharged from the Plug Holes and if there is a Spark

hope im not hijacking the thread.
if i dont have a few beefy wires lying around to ground all plugs, will removing the lanyard from the kill switch work as well ?

about to do a compression test myself tomorrow....

 

[jimmbo]

hope im not hijacking the thread.
if i dont have a few beefy wires lying around to ground all plugs, will removing the lanyard from the kill switch work as well ?

about to do a compression test myself tomorrow....

It should. More than one Skipper has had a No Start problem, that was caused by Kill Switch activation

 

[so]

It should. More than one Skipper has had a No Start problem, that was caused by Kill Switch activation

do i unplug fuel hose as well?

 

[so]

Normally done COLD !!----Plugs out.----Pull it over with a recoil till gauge stops going up.-----No need to open throttle on a 2 stroke.

maybe a dumb question, but what is the reason for not needing wot on a 2 stroke?

 

[racerone]

Intake and exhaust ports are WIDE OPEN at the bottom of the stroke.----Cylinder is full of air then.-----Compression does not start till piston closes exhaust ports.-----When you understand how things work it is much easier to trouble shoot !!