Good afternoon. My 1979 8hp Mariner lower unit won't come off. I've be trying to get to the impeller because the engine has been overheating and I beleave the impeller to be the problem. Please help. Thanks.
Do you have ALL the bolts & nuts off?? Sometimes they hide one or two on you... Is corrosion the problem... A good dose of PB blaster or WD40 should help.. let is soak.. Last resort try heat.....Check for a bolt on the underside of the cavitation plate right above the prop... DO YOU HAVE A MANUAL?
__________________
Now understand, Commander...
That torpedo did not self destruct...
You heard it hit the hull...
And I...Was never here...
There are (4) bolts that seem to hold the lower unit on. When I remove them, it drops apx. 1/4". I have removed the screw above the prop, and didn't do anything.
Have you tried a LITTLE force? sometimes the water tubes and or the drive shafts stick from corrosion..A wood block and a rubber mallet might help or pry as a last resort.. DO U HAVE A MANUAL. There's other stuff you need to know about like position of the shift shaft for reasembly ECT....
__________________
Now understand, Commander...
That torpedo did not self destruct...
You heard it hit the hull...
And I...Was never here...
I have wacked it pretty hard a few times with a rubber mallet, and it didn't seem to move. I ordered a repair manual last week and it hasn't arived yet. Someone said something about putting it in gear to remove the unit? Still didn't work.
I'd have to say the drive shaft splines on the crankshaft are rusty, the shift shaft too possibly..It's gonna take some force.. You might try turning the beast upside down and give everything inside the drive shaft housing a healthy dose of penetrating oil.. just make absolutely sure theres no water in the engine..Then wait for the manual in case we missed something....
__________________
Now understand, Commander...
That torpedo did not self destruct...
You heard it hit the hull...
And I...Was never here...
I received my manual on Sat. and set out to concour this beast. I did everything as per the manual and still the lower unit would not come off. So I decided to get a HAMMER and a 2x4. Whack, whack, CRACK. I broke one of the lower side fins off. I'm not sure what to do now?? Thanks.
Cavitation plate can be re welded and shaped after you are successful in removing lower unit,as long as it didn't fracture prop shaft housing.Not familiar withyour motor but if there is a shift shaft pin bolt not removed maybe that is your problem.had a friend with 6 hp merc and it had a shift rod pin bolt .7/16 hex.
This view is your entire shift assembly from the gear shift selector to the lower unit...Locate the cotter pin (part #13 on the view)near the shift selector by the power head and remove it.. This should allow the lower unit to drop far enough to access the bolt and shift rod connector(parts #15-18)... You should be able to see the bolt and connector between the lower unit and the drive shaft housing.. Remove the bolt and seperate the connector... Thats it..
__________________
Now understand, Commander...
That torpedo did not self destruct...
You heard it hit the hull...
And I...Was never here...
I unfastened the linkage and the lower unit will still not come off. I can feel the clunk when it moves a 1/2" and stops, but can't figure out whats holding it back?????
can you get clear view of shift rod and know that there is no attachment clevis on it that wont clear grommet tube?because if it is disconnected the only other possibility is the driveshaft somehow is binding.
Weird deal ,the only thing i can imagine would be the driveshaft somehow.If you haven't already try working unit up and down to see if 1/2 " changes at all as driveshaft binding on spline.
1979 Mariner 8hp lower unit won't come off.
DO YOU HAVE A MANUAL? 
if you have your serial # you can find the view of gearcase.. 
Linear Mode
