1985 omc 3.0 litre. The problem is slow cranking like a dead battery. I put a brand new battery and nothing. I put a brand new rebuilt starter. Same slow cranking. Now it wont even turn just buzzes. I hear a buzz when the key is turned.
If it sounds like the starter is turning but not engaged to the flywheel check the starter bolts and make sure ones not broken. Also check your ground cables.
+1 - this is a fast test to help isolate the problem. An upper gear-case that is jacked up will give ya' problems. Doing this test will tell ya' which side of the transom your problem is more likely on.
Have you checked the starter solenoid? If it is burnt internally (and that happens real easy too) it will not flow the proper current to turn any faster. Just a thought. I just within the last week had such a problem myself. It was the starter solenoid...
