Cranking Power Loss

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!

Sounds like classic bad battery. Next time it pulls its routine, put your hand on the side of the starter. If it is very hot (don't burn yourself!) you probably have a bad starter (shorted windings in the field, or armature). The "heat-test" works with the cables too. You can run your hand across any suspect area & see if it is getting hot too.

martino1 said:

Sounds like classic bad battery. Next time it pulls its routine, put your hand on the side of the starter. If it is very hot (don't burn yourself!) you probably have a bad starter (shorted windings in the field, or armature). The "heat-test" works with the cables too. You can run your hand across any suspect area & see if it is getting hot too.

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Thanks Martino, you're probably right as someone in my office suggested the same thing this morning. It isn't the battery though because when I switch out the old one w/ the new one I get the same results. I'm betting the starter will get hot when I try again this evening.