I AM LOOKING AT A 79 85HP V4 JOHNSON TO PURCHASE AND I WOULD LIKE TO CHECK COMPRESSION BEFORE I PURCHSE IT. MOTOR HAS NOT RUN SINCE 92, WAS FOGGED, BUT I WILL NOT BE ABLE TO START IT TO TEST COMPRESSION. I HAVE CHECKED COMPRESSION MANY TIMES ON AIRCRAFT ENGINES BY SCREWING IN GAUGE AND HAND TURNING THE PROPELLER. CAN I PUT THE JOHNSON BOAT ENGINE IN GEAR AND HAND CRANK THE PROP TO GET A COMPRESSION READING??? OR TURN PROP NUT WITH WRENCH UNTIL I GET TO CYLINDER UNDER TEST??