I replaced the original Johnson 40 HP w/ a newer 70 HP motor which had been sitting behind the previous owner's house and not run for a while (1-2 yrs.?). Using the original battery (550CCA), the replacement motor will fire when cranked, but then after it's cranked 3-4 times it appears to drain the battery (not enough power to turn the starter). Thinking the battery was the problem, I replaced the battery (500 CCA) and it would do the same thing. I've cleaned all electrical connections , the starter brushes and coil, and replaced the starter selonoid and the rectifier. If I let it sit for a while it will again crank a few times, then lose power. Any ideas what to look for now? Thanks in advance!