1979 Mariner 8hp lower unit won't come off.

[mcslee]

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.

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

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?

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

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.

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

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....

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

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.

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

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....

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

mcslee Check out this website It shows exploded views of everything.. if you have your serial # you can find the view of gearcase.. <br />www.mercruiserparts.com/SelectProductLine.asp

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

Thanks for the info. I'll give it a shot. Chris

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

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.

 

[ob]

Re: 1979 Mariner 8hp lower unit won't come off.

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.

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

Sorry to hear of your OUCH...I'm stumped too... It's been a while but I don't recall any bolts or pins holding the shift shaft..

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

go to this site and click on gear shift linkage... Check the exploded view..I think you'll find your problem...<br />www.mercruiserparts.com/select_docs3a.asp?doc_nbr=+83774+++

 

[ob]

Re: 1979 Mariner 8hp lower unit won't come off.

Looks like there is one

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

I stand correceted....

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

I'm not sure what your looking at how how to get to it. Please explain. Based on the Pic. Thanks

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

I'm not sure what your looking at or how to get to it. Please explain. Based on the Pic. Thanks Sorry about the spelling.

 

[snapperbait]

Re: 1979 Mariner 8hp lower unit won't come off.

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..

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

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?????

 

[ob]

Re: 1979 Mariner 8hp lower unit won't come off.

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.

 

[mcslee]

Re: 1979 Mariner 8hp lower unit won't come off.

Yes I can clearly see the shift shaft. After I unbolted the clamp, you could see that nothing was at the end of the shaft..