Logo
FULL SITE MENU

Mercruiser 120 lower end

P

pat71442

New member
"How do I replace th lower end

"How do I replace th lower end of a mercruiser 120 after replacing impellar. Each time I put it back together I cannot shift it, what am I doing wrong?"
 
Shifter in forward. Set shift

Shifter in forward. Set shift lever on LU straight forward then install LU.
 
"what is the shift lever, the

"what is the shift lever, the slots by the shifting shaft, how do you turn it.? it goes into forward and nuetral, but not reverse."
 
"GUY: NO THIS IS NOT HOW THE L

"GUY: NO THIS IS NOT HOW THE LOWER END LOOKS, IT DOES NOT HAVE A DRAIN PLUG AND THE ANODE IS HELD ON BY A BOLT. HOW DO I FIND THE YEAR OF THE MOTORS??"
 
"PAT

1. WE DO NOT USE CAPI

"PAT

1. WE DO NOT USE CAPITAL LETTERS AS THAT SIGNIFIES YELLING/SHOUTING.


You must have the shift control in forward!!!!
When reinstalling the lower to the upper you must turn the SHIFT SHAFT (male splines) fully clockwise and spin the prop counterclockwise until it locks!!!!!!!

Hold the prop secure, make sure the shift shaft does not move, get the water tube aligned that is or should be sticking out of the water pump assembly, as you push the lower up there is a BRONZE shift arm (with female splines) in the upper that MUST alighn with the shift shaft male splines. The bronze arm MUST BE POINTING AT 12:00 OCLOCK/STRAIGHT FORWARD.

What is happening is the male splined shift shaft is not fully clock wise befor its engament with the bronze shift arm!!!!"
 
"Sorry aboput the caps, certai

"Sorry aboput the caps, certainly was not shouting...Thanks I will try it, the shifting bronze arm is the issue I did not understand the 12 o'clock thing, and may not sstill. I am going to drop the unit again right now and will see if I can understand it, oops just learned I have to get going to a reunion, memory at my age is at a minimum. Will try later and let you know... Pat"
 
To set the LU shift shaft in F

To set the LU shift shaft in FORWARD turn the short splined shaft fully clockwise; it's located at the very front of the LU. To keep it in forward gear while aligning the two halves hold the prop in position w/a little COUNTER clockwise pressure. The boat throttle/shift lever must be in forward. Align the LU parts to the upper parts while sliding the two halves together. Make sure the male splines of the LU shift shaft mesh w/the upper half female splines of the upper shift shaft. AFTER they have meshed together rotate the prop COUNTER clockwise to assist in connecting.
 
Kghost:

Thanks for your exp

Kghost:

Thanks for your explanation. I was digging thru pics. on-line for illustration and just couldn't find the right one. I finally dug out my Merc. OD manual and read the procedure which you already posted.
 
"Just one more question, is th

"Just one more question, is the washer on top of the rubber on the male spline supposed to be indented in the middle? this one looks odd, bent unevenly...Pat"
 
No The washer should be flat.

No The washer should be flat. there should also be a rubber washer under that if I remember correctly.
 
"How do I know the female spli

"How do I know the female spline is at 1200? Is there a marker on it? I have the male spline all the way to clockwise, prop is taped in place so it will not move, the shifter is in forward, so I'm ready to put it back together, but cannot figure out the female spline. It will lock in place at one point is that 1200? Pat"
 
Turn the splines all the way i

Turn the splines all the way it can go clockwise with you hand or a small pair of pliers and TURN THE PROP C'CLOCKWISE AND HOLD IT THERE. This will keep the splines at 12:00.

It is a bit of a jugguling act so be patient and careful.

As you get everything aligned and the drive shaft may not be just spin the prop c'clockwise and the drive shaft will turn.
 
"If you are speaking of the br

"If you are speaking of the bronze piece then as the lower splines get close make sure it is at 12:00 and it WILL line up/fit over the splines.

The bronze piece is floating so it can and people do just let it "fall" where it may, This is why after reassembly it does not shift correctly."
 
"I got it all buttoned up and

"I got it all buttoned up and no gears...I did however forget to replace the washer on the drive shaft, could this be the overall problem? In testing the other motor, failed impeller there also, so I will get more practice than I had planned. Thanks for all the help, pretty soon I'll get this, I will not break down and have some one else do it...Pat"
 
Back
Top