Compression testing question

[Romey55]

Question, i have a troy bilt ,ryobi and bolens weed eater (which i found on the road ) . If i screw in the compression tester all the way in on the ryobi and bolens , i cant pull the string . No problem with the troy bilt . If i unscrew the tester a few turns i can pull the string . Does it matter ?

 

[bertsmobile1]

YES with a capital Y
To get meaningful readings on these very small volume engines you need heads for the compression tester that are exactly the same size shape & volume as the spark plug .
So my set has 4 heads it came with and a dozen more I made

 

[StarTech]

Plus it must be sealed and it matters where the check valve is located in the hose. It must be at the cylinder end and not at the gauge. I use an Actron tester and never had a problem like you describe.

 

[4getgto]

Is he saying the adapter is screwing too far into the head hitting the piston.?..not sure I'm following .

 

[StarTech]

Is he saying the adapter is screwing too far into the head hitting the piston.?..not sure I'm following .

That what I am thinking as there is a long version my kit.

 

[Hammermechanicman]

They make testers specifically fir small engines.

 

[slomo]

Good to have a short hose. LOL