Reply To: compression 57 3 hp Johnson

[David Stanton]

You are right if the check-valve is at the engine end of the hose, then the hose will build up compression pounds with each stroke. If the checkvalve is at the gauge end of the hose, the compression in the hose is lost each time the piston backs up. I have a gauge like that and it gives me about 20 pounds less on a 3 HP Johnson. The amount or error will vary from gauge to gauge depending on the volume of the hose. On bigger cylinders, the volume of the hose becomes less significant.
Dave