Re: compression check for 56 evenrude
Buy a compression tester at an auto parts store. Remove spark plugs, keep wires on them. You need to ground the spark plugs to the engine block to avoid damaging the ignition system. I use alligator clips which go around the spark plug threads and the other end goes to any bolt on the powerhead. Then screw the compression tester into a cylinder and give the rope pull about six pulls or until the tester gauge maxes out. If electric start, just crank her over for a few seconds. Record the reading. Then do the same for the other cylinder. Readings should be within 10 percent of each other. Readings should be a minimum of about 90psi for that motor. This is a good time to check spark also to see if the coils are good.
