Re: Can't get gearcase off 1978 6hp Evinrude
The link that holds the upper and lower shift rods together, is located in the area of the water pump housing, inside of the midsection.
Remove the four bolts that hold the gearcase to the midsection. Shift the motor into reverse and pull the gearcase down, until you have about a half inch space between it and the midsection. Now look into the gap - you will see a brass link with two bolts in it. Those bolts will also have a screwdriver slot in them. Remove the bottom bolt, so that the lower shift rod can be pulled out of the link. Pull the gearcase down again to separate it from the midsection.
If the gearcase still won't separate fully, rotate the prop (remember that you shifted it into reverse), so that the driveshaft rotates in a clockwise direction, as viewed from the top. There is a rollpin in the upper end of the driveshaft, that must be aligned with a slot in the upper portion of the midsection. Once the two are lined up, the gearcase should separate fully from the midsection.
You will have to remove the rollpin to get the water pump impeller off of the driveshaft. Do not forget to reinstall it when reassembling the motor! The function of the roll pin is to compress and hold into place, a seal assembly that rests in a compartment in the upper end of the midsection. That seal assembly is what keeps water out of your powerhead casing. Failure to replace the rollpin, may result in water intrusion and eventual seizing of the crankshaft!
PS: The reason why I shift into reverse instead of forward, is because it pushes the shift rod down and that gives you more of a gap between the gear casing and the midsection.
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