i took my new used boat out for the first time, 1988 80 merc 3cly. rode about 15 minutes water was pumping out of drive great but the shifter started to make noise like an overheating alarm , so i shut motor of then tryed to start it it would not crank so i for some reason checked batt..terminals for tightness as i put charged batt in ,it started right up and we rode it for at least 5 miles no problem, 2nd question how can you tell if oil injection is working???<br />the motor is fresh water and clean