Compression Tester Hitting Top of Piston? Old Echo GTR-200R Curved Shaft Trimmer

[cao-2000]

I am diagnosing an old Echo GTR-200R Curved Shaft Trimmer for my neighbor.

I grabbed my compression tester, and I'll be darned if it doesn't seem to be hitting the top of the cylinder when it is screwed in all the way. So I grabbed a different compression tester, and same thing.

Is there a different (shorter) threaded piece I need for these smaller 2-stroke engines? Or maybe a different compression tester kit that might have it?

See photos for my current compression testers. One is an older generic, and the other is a new Lisle.

Thanks,

Chris

 

[srcarr52]

Ditch the adapters and just use the threads on the end of the hose.

 

[cao-2000]

Ditch the adapters and just use the threads on the end of the hose.

I will give this a try. If it works, I will feel dumb...

 

[Duce]

If those adapters do not have valve at it’s end, you will get low reading.

 

[r7000]

match the tester fitting to the spark plug, see how much of a distance difference there is.

you can back off the tester with whatever adapter fitting that's hitting the piston, a 1/2 turn or whatever until it doesn't hit the piston - open the tester valve so there's no compression to facilitate spinning the motor. Then wrap a little teflon tape on the tester fitting threads and don't screw all the way in only to the distance that seems appropriate, it'll seal well enough to get a good enough compression reading, just don't get the tape into the cylinder.