ABN Compression Tester and Adapter - 14mm Dual Automotive Compression Gauge with 18mm Compression Tester Adapter

This inexpensive compression guage has all rhe accuracy and features of a much more expensive guage, including quick disconnect and interchangeable screw thread sizes. Most importantly, it has a scrader valve at the spark plug screw-in end piece, assuring no loss of accuracy. I measured this guage against my old but hight quality guage on the same chainsaw engine and got exactly the same reading (175 psi) on both guages. Interestingly, I only got 105 PSI when I quick connected either this or my higher quality guage to the tubing from a cheaper compression guage kit that did not have the shrader valve on the business end. I was getting very low readings using that defective old kite and threw the guage away, but kept the hose. Turns out there was also a problem with the hose in that cheap kit as it lacked an authentic shrader valve at the screw-in fitting. Make sure any compression guage hose that you use, has a schrader valve on the threaded end, as well as an air pressure release valve at the indicater end. The cheap guages have only a flap valve and those leak air under pressure. The better guages (including this inexpensive one)l have both an authentic, replacible schrader valve, and a release valve. I saw a utube video describing this and didn’t believe it. But trust me....it makes all the difference in the world.

I compared the Guage with another Compression gauge and I am satisfied with the Results.

First one I bought didn't do anything except the needle would move a little bit and then go back to zero would not hold compression so I got a hold of the seller and they sent me a new one which I thought was very good of them but that one also did the same thing basically nothing. I have my own lawn care business so I work on small equipment all the time and I know how to use one but this one just didn't work, I don't know if I just had bad luck with the two of them and got too bad ones in a row or if everybody out there what's going to the same thing I was.

1. It works as described. Unscrew the spark plug and screw this in.2. The 14mm adapter is threaded so it fits into the 18 mm. Just unscrew the 18 off to use the 14mm.3. It is very well made and the pressure reading stays until you push the release button.

I asked Rufus if it had a Schrader valve, and the answer was yes. When I looked at it upon delivery, it had no Schrader Valve.

Not used yet but great value if it works.

But it would be better if the check valve worked. Reached out to the manufacturer but no reply.EDIT:checked it out further and discovered that the pressure release button is adjustable and was set too deep so it was bleeding down. It now functions properly.

I bought this for use with small engines, so the adapter it came with was nice. It appears to be accurate, based on my "arm calibration" of using a pull start rope and feeling the compression, this seems to be about right. No complaints so far with this compression tester.