Logo
FULL SITE MENU

Dropping Lower unit off 15 hp Merc

M

mlmarkee

New member
Hello
Completely new here and new to trying to fix my own outboards. I've got a 15 hp Merc--I believe to be mid 80's by the serial numbers, but I am not quite sure with the way they run their serial numbers. Anyways, I think my impeller is busted on my motor, or that is where I am going to start looking, however I am having issues getting the lower unit to drop off. I have taken the 3 bolts off, but I can't get the shift shaft to disengage. On a rough schematic that I looked at, it almost appeared that the end of the shift shaft could be threaded, but I am not sure. Anyways, I can't figure out how to get it disengaged so I can take a look at the impeller. If anyone can tell me what the deal is with this shift shaft, that would be awesome! Thanks in advance.

 
If it's a mid '80s, there is a clip sort of under/behind the carb that you flip open and remove a pin and this releases the shift rod from the linkage
May be easier in forward gear if I recall
 
Umm, on second thought, I can't quite remember what the motor year is--the serial number is A743570. So maybe I am off on the date if this helps with what type the motor is.
Thanks
 
The listing I have references a 1990 20 hp merc (canadian #), either way I believe the rod would be the same from about 1987 onwards. Prior to that the shift rod had not pin or alike on portables
Maybe someone else has a more acurate listing for the year if mine is incorrect
 
Yes, Canadian built (post 87 - my Canadian records suck because Merc/Mississauga had crappy records).

Anyhow, the top of the shift shaft is held on by a little clip.

The shaft itself comes up through the lower cowl and is (sandwiched) between the ears of the shift cam.

A clip (with a horizontal pin) goes through the cam holding the shift shaft in place and is locked over the end of another shaft that goes to the other side of the block.

To remove the clip it's easiest to grasp it with a pair of needle nose pliers and move it "upward" to "unclip" it, then pull the whole thing towards you and right out of the engine compartment.

It may sound confusing, but once you have done it one time you will totally understand what I'm saying (and never forget how to do it again).

This clip/cam is located (under) the front of the powerhead, almost directly behind the carb. If you have an electric start model, you must remove the starter to gain access (which is really tight regardless).

Here are a few pics of what/where you looking for/at :)
 
Last edited:
Wow--you guys are awesome! I have somewhere to start. So, after I release the shift shaft at the top, does it just slide all the way through and come off with the lower unit? There is some little square stopper thing on the outside of the unit on the shift shaft--do I just take that off to slide it through the housing just above the lower unit? If this doesn't make sense, I will try to take some pics of what stopper thing I am talking about on the outside.
 
And that "little stopper thing" is what disengages the tilt lock when in forward gear - in case you hit something submerged it will allow the motor to swing up protecting the lower unit from parting company with the rest of the motor.

If you haven't removed it already you can either mark it's location on the shift shaft or simply shift the motor from neutral to forward a couple of times so that you can observe how it works for when it comes time to reassemble...
 
Back
Top