Mercury YU2Z-6108-EA Piston And Pin Assembly

Check the piston-to-bore clearance by measuring the bore and the piston diameter. Make sure the pistons and bores are correctly matched. Measure the piston across the skirt, at a 90-degree angle to and in line with the piston pin. Subtract the piston diameter from the bore diameter to obtain the clearance. If it's greater than specified, the block will have to be rebored and new pistons and rings installed.

Lubricate the piston and rings with clean engine oil and attach a piston ring compressor to the piston, leaving the skirt protruding about 1/4-inch to guide the piston into the cylinder.

Remove the bearing insert and push the connecting rod/piston assembly out through the top of the engine using a wooden hammer handle to push on the upper bearing surface in the connecting rod. If resistance is felt, double-check to ensure that all of the ridge was removed from the cylinder.