Re: Early 70s 85Hp Mercury Blueband with Thunderbolt Ignition Problem
Put the motor in neutral, before you drop the gearcase. Make sure you remove the zinc anode above the prop, since there is a bolt under it that has to come out. Remove all bolts and drop the unit. Remove the rubber slinger and waterpump cover. Inspect cover for scoring. If you find it, replace the cover. Drain some gear oil, if it is milky, replace waterpump base. Sand driveshaft to clean it up, and oil it, if you need to remove WP base.
Replace impeller, SS wearplate, gaskets on each side of wearplate, and oring and gasket under WP base. Install slinger and water guide tube, and grease splines on driveshaft and shift shaft, and reinstall gearcase. As you shove the gearcase into the midsection, turn the flywheel by hand to match the splines. The gearcase will wiggle into place. Do not force it. Now add marine gear oil thru the lower plug hole until it emerges from the upper hole. Install the upper plug with a gasket, and then the lower plug with gasket.
Put the motor in neutral, before you drop the gearcase. Make sure you remove the zinc anode above the prop, since there is a bolt under it that has to come out. Remove all bolts and drop the unit. Remove the rubber slinger and waterpump cover. Inspect cover for scoring. If you find it, replace the cover. Drain some gear oil, if it is milky, replace waterpump base. Sand driveshaft to clean it up, and oil it, if you need to remove WP base.
Replace impeller, SS wearplate, gaskets on each side of wearplate, and oring and gasket under WP base. Install slinger and water guide tube, and grease splines on driveshaft and shift shaft, and reinstall gearcase. As you shove the gearcase into the midsection, turn the flywheel by hand to match the splines. The gearcase will wiggle into place. Do not force it. Now add marine gear oil thru the lower plug hole until it emerges from the upper hole. Install the upper plug with a gasket, and then the lower plug with gasket.