1969 Evinrude 40 HP Big Twin, Big Twin Electric Lark Service Manual 4596, Page 52Get this manual
Figure 5-24Checking Ring Gap in Cylinder Before installing new piston rings, check gap between ends of ring by placing ring in its respective cylinder bore, then pushing the ring down in the bore slightly with the bottom of the piston to square it upDiscard and replace with new ring if gap is excessiveSee Figure 5-24Check each ring in its respective ring groove for evidence of tightness or binding by rolling the ring around the piston ring grooveSee Figure 5-25Check for groove side clearance with feeler gageSee Figure 5-26 Correct gap and side clearances are given in Section 2 Figure 5-26Checking Groove Side Clearance and free from dirt and gritPerfectly good cylinder walls, pistons and rings can be ruined in few minutes of operation unless all forms of grit are removed before assemblyWork in clean surroundings and with reasonably clean handsCoat all bearing surfaces, cylinder walls, etc, with clean oil before assemblyNOTE Always use new gaskets and seals throughout when reassembling the power headPISTONS, WRIST PINS, AND CONNECTING RODS aThe relative positions of pistons and connecting rods must be considered when assembling pistons to rodPistons must be installed in cylinders with intake side of piston toward intake portSee Figure 5-27Oil holes in connecting rod must be toward top of motorSee Figure 5-28bApply coat of oil to wrist pin, making sure surface is cleanPlace drop or two of oil in each pin hole in the piston