Re: compression gauge for cars will it work on my johnsons 1973 85hp?
Be sure to check the thread lenght.. most gauges come with a long reach and short reach end.. if you screw the long reach one in it will hit the top of the piston.. not good for the motor and defently not good for the gauge... Most likely will have the long reach end on when they come out of the package... Alot of them have a 2 piece end.. just unscrew long straight part from the short part that connected to hose... Again check the thread lenght against your plug's thread lenght...