Mercury L5 Gearbox Install - Clutch Alignment

[Onegazza]

The lower unit has been re-installed in forward gear with the shift rod in forward gear (fully rotated clockwise) and, with the remote in forward gear. The remote is moving normally between forward, neutral and reverse and I can also see the shift rod on the lower unit moving accordingly so, this is all aligned. I checked the alignment of the cam shift control (part side up, fully rotated clockwise).

The gearbox is stuck in forward gear - the cam shift control is moving but, doesn't seem to be engaging the clutch.

So, all of this points to the clutch not being aligned/engaged. So, is there some special way with these lower units for them to be installed or aligned, in order to get it to function or "click" into place? At the moment, the shift rod and cam shift control are functioning correctly but, it's not moving the clutch.

(FYI the clutch was not removed from the prop shaft when the unit was taken apart and, the unit was re-installed with the cam follower and ball bearings as they should be)

 

[Onegazza]

The photo shows the prop shaft and dog clutch before reassembly

 

[racerone]

Motor type and serial # required.----More pictures of the gearcase and also the shift rod end.

 

[Onegazza]

Motor is a 99 Force 120HP outboard. Serial it has a Mercury serial number of 0T051311 but, this doesn't return a result on any of the Mercury part finders (potpotentially something to do with it being one of the very last Force engines and was actually assigned a Mercury engine number). The number stamped on the block is 100598.

Photos below.

 

[Onegazza]

(posted in the Mercury section because, the question is about the Mercury gearbox)

 

[racerone]

Remove lower unit.------Find neutral on the lower unit.-------Put control box in neutral.-----Install lower unit.-----Make sure it does not jump into forward during assembly.

 

[Onegazza]

As above, the cam shift control is moving but, doesn't seem to be engaging the clutch.

 

[racerone]

??------It takes a bit of effort to turn shift shaft COUNTERCLOCKWISE to put it in neutral.----Or hurry to a shop to help you.

 

[The Force power]

With the LU on the bench or in vise put a 9 mm Socket on the shift-shaft for leverage (do not use pliers!!)
Turn the drive-shaft clockwise WHILE shifting in forward or reverse
IF....that will not work.....take it apart, something is wrong inside

with the older Mercury LU's it was possible to "over turn" clockwise (while on the bench) I'm not sure about these ones

 

[Onegazza]

Let's apply some logic to this.

The shift control rod is moving and therefore, the cam is also (but only with a fraction of a movement of the propeller anti-clockwise).

With this gearbox, does it require driveshaft rotation in order to engage a gear? If so, I can just turn the flywheel with a ratchet, whilst someone changes gear with the remote.

What still doesn't make sense is if you crank the engine in neutral, the prop spins in forward.

 

[Chris1956]

Merc gearcases have 3 cams on the shift mechanism. These cams position a shift rod, against a spring to push the shift dog to the correct position to engage either gear, or neither (neutral).

There is a lot of shift cam, past the spot that engages forward. When you turned the shift rod CW, you moved the shift cam past where the available shift shaft "throw" can engage neutral or reverse.

As was suggested in post #6, set the shifter to neutral and the control to neutral and install the gearcase. You may need to rock the throttle arm on the control to align the upper and lower shift rods.

 

[racerone]

When you figger it out you will say ------" that really was easy "--------Just my opinion.----In post #1 you said ---" shift rod fully clockwise "----That might be mistake #1

 

[merc850]

Let's start at square 1 did you install the cam like in pic Nr.1?
if so then continue to set up the shift shaft by turning it by hand COUNTER CLOCK WISE until it stops - it will still be in F - then with Vise Grips tight on the bottom of the shaft turn it a
few more degrees CCW until it clicks into a stop, this
should be neutral - check by turning propshaft --
prop should spin freely.
Put control in N and go ahead and attach LU to driveshaft housing some turning of the flywheel will help the DS splines align.
Do not shift into reverse unless you turn the prop at the same time.
These instructions are for older engines but they should apply to yours too.
Grease the drive and shift shafts before installing.

 

[The Force power]

What still doesn't make sense is if you crank the engine in neutral, the prop spins in forward.

When everything is working as it should; you will see the prop turning while in neutral. that's caused by oil in the lower unit.
BUT...the prop SHOULD STOP turning with any little resistance

 

[Onegazza]

Resolved.

Some responses above aren't correct.

The correct solution was driveshaft input and re-installing the gearbox in neutral (as a result of driveshaft input and a 9mm socket on the splined shift rod) - the travel on the cam is tiny in neutral so, much easier to align with the shift rod in the leg.

The manual is misleading, where it says to remove and install in forward gear. I found this almost impossible to re-install.

 

[racerone]

And what is NOT correct ?

 

[Chris1956]

If you really want to install the gearcase with the motor in forward, it can be done, but it is a PIA. You would need to put control and gearcase in forward, and just before the shift shafts align, turn the gearcase shift shaft CCW to stop and then install it.

 

[merc850]

I don't know what an L5 gearbox is; the instructions I posted were for older motors so if they worked then I will continue to answer questions with them, if not, then let me know.

 

[GA_Boater]

L5 gearbox puzzled me as well. Not wanting to show my lack of knowledge of the "new" Merc/Force, I didn't ask.

So what is an L5 gearbox? Is it a Force L drive?