70 hp lower unit removal

[johndeerenut]

i can take an old tractor or car and completley rebuild it from the ground up but when it comes to boats im plain stupid.i just bought my first boat a 1982 starcrafy ss 160 with a 1975 70 hp evinrude.i am going to replace the thermostat and waterpump in it. how do i remove the lower unit i have been told there is a bolt in the middle of the motor that has to come out for a shift linkage to be loose so the lower unit will come off. does anyone have pics of this removal process any help is greatly aprecciated.also i can find no signs of a tell-tale line at all on this motor should it be this way and i am real leary of drilling the block will it hurt to not have one.the model #is 70573b and the serial # is jooo5369 t thanks brian

 

[jtexas]

Re: 70 hp lower unit removal

Water pump replacement
1. disconnect shift linkage, 5/16" hex head screw under the bottom carb (move the fuel pump out the way for better access).
2. remove the trim tab (scribe a mark across the edge so you can get it back like it was).
3. remove the retaining bolt up in the trim tab cavity.
4. remove the other retaining bolt from the bottom side of the antiventilation plate.
5. remove the four retaining bolts from the perimeter, just above the antiventilation plate.
6. pull the lower unit off.

the shift rod height is adjusted by screwing it in or out, so don't twist it or else it won't fit when you put it back.

7. Don't forget the grommet around the driveshaft
8. Four hex-head screws hold the water pump housing down.
9. Slide the old impeller off the drive shaft.
10. Slide the new one on. Slip the woodruff key in place just before the impeller covers the keyway.
11. Put a new housing gasket in place.
12. Grease the inside of the housing (trailer axle grease is fine), and shove it down onto the impeller while turning the driveshaft clockwise with your hand. Don't use any kind of tool on the driveshaft splines.
13. Fasten the housing back on.

On reassembly:
* put molly lube on the drive shaft splines (but not on top, there's not enough clearance).
* the rubber o-ring just below the drive shaft splines -- you need that.
* put omc gasket sealant (or some kind of anti-sieze) on the retaining bolts -- or else corrosion will set in & it'll be a ***** next time.
* use 3m #847 or permatex #2 on the joint between midsection & lower unit -- permatex is way harder to clean off there next time around.