Maybe it just needs to break in a little?

The easiest way to have confidence in a new compression gauge is to compare it with a “known good” gauge.  Maybe a friend has one?

I see posts all the time about incorrect readings from the typical Harbor Freight gauges.  The other thing to be aware of is the location of the valve.  For small displacement engines it is better (more accurate) to select a gauge with the valve right at the motor end of the hose.  Reason being is that you do not have the extra volume of the hose to fill;  adding to the displacement of the cylinder if you will…..

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Rkymtn57

Just demonstrate it running and don’t mention compression.  Nobody I’ve sold or given motors to has asked about compression.  If someone asks, just say you don’t know but have them pull it over to see there is a good, hard, compression feel.

I got a compression gauge at a NAPA auto parts store with the valve at the motor end like others mentioned.  I had an old Sears one made for cars with the valve at the gauge and it gave me a lot of low readings.  On big cylinders in cars, the Sears one worked OK.

Dave