150 Johnson compression test not running

[SoldierBoater]

I have a 1985 Johnson 150hp and I need to do a compression test on it... it hasn't ran in about 5 yrs and is not hooked up to a fuel tank nor has any spark plugs... can I just twist the top and get readings or is there something else I need to do

 

[jonesg]

Re: 150 Johnson compression test not running

Why not connect a battery and crank it. Jump the solenoid.

 

[emdsapmgr]

Re: 150 Johnson compression test not running

You need to spin the flywheel at 200-250 rpm with the plugs out in order to get any valid compression reading. As Jonesg said that's normal starter cranking rpm's.