Re: 90 Merc forward & Rev backwords
hope I can help you, first shift the rearcase into neutral position Loosen the jamnut above the shift coupler, then turn the shift rod coupler until the upper and lower shift rods are separated. mark the trim tab position and remove the trim tab retaining screw, you will notice the slide on the top shift tab move back into the motor.remove all the nuts to the lower unit. remove the water tube if it still in the upper part of the housing place it on the water pump. inspect the driveshaft spines if I'm not mistaking there will be a white plastic washer and a small shift shaft on the lower unit infront of the water pump, turn that all the way to the left do not over turn it. check all the shafts lubricant the top of the driveshaft,dont over lubricant it will not sit completely in the crankshaft.Now to reinstall the lower unit make sure the water tube guide and seal are securely attached to the water pump. Push the gearcase towards the driveshaft housing, if the driveshaft does not go in with ease you have to turn the flywheel clockwise not counter clockwise, you can damage the spines and the water pump impeller. when reinstalling the shift rods the top one will have to meet up with the screw, but remember the slide that slid into the motor has to move out with a little force and then align the nut up. and re install all the bolts to the lower unit, make sure your water pump is working. hope it helps
