Need help with a 1977 Mecruiser 120 I/O

[rbthntr64]

Guys,
Sorry for the hijack of the old thread. I just bought a 1977 RSB Fiberglass Forms "Fishmaster" boat. It is a 15' tri-hull with a Mercruiser 120 I/O drive line. THe ratio in the sterndrive is 1.98. The shift cable is completely missing, so I am needing help to identify and order one. I know this site has them, but I do not know what to order. I downloaded the manual, but it does not show a breakdown of the mercontrol box. Any help is greatly appreciated on the boat and the drive.
THanks
The New Guy

 

[180shabah]

Re: Need help with a 1977 Mecruiser 120 I/O

Upper shift cable or lower shift cable?

Upper = from control to "engine"
lower = from "engine" to drive.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

Upper shift cable or lower shift cable?

Upper = from control to "engine"
lower = from "engine" to drive.

Upper. After looking closer, the cable is there. I will most likely be back with more Q's. THanks for the help.

 

[180shabah]

Re: Need help with a 1977 Mecruiser 120 I/O

We'll leave a light on for ya'

 

[chiefalen]

Re: Need help with a 1977 Mecruiser 120 I/O

Maybe it's me, one minute it's not there, next it's there.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

Maybe it's me, one minute it's not there, next it's there.

THe guy I bought the boat from told me it wasn't there. Upon closer look it was laying in the bottom of the engine compartment. A good thing because this boat is anything but standard.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

My brother up in Michigan told me to drop the lower unit and check the condition of the impeller. THis is what I found.

 

[fishrdan]

Re: Need help with a 1977 Mecruiser 120 I/O

Looks like it's been run without water going to the outdrive,,, running the engine on land without using muffs. Need to replace the impeller and housing, get the complete kit.

 

[chiefalen]

Re: Need help with a 1977 Mecruiser 120 I/O

Some of the pieces are missing, on the impeller.

You have to find them.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

The little drive dog was in there as well as the guide tube for the water tube.
I am ready to go back together and need to know what position to put the little spline gear in relation to the shift lever? Anyone have any pointers? BTW, Want to say thanks again for all the input. I hope that others are learning as I proceed with my winter projects.

 

[Bondo]

Re: Need help with a 1977 Mecruiser 120 I/O

Anyone have any pointers?

Ayuh,...

Go over Here,+ download the Factory Manual for your drive,+ motor...
It'll answer All of your Questions,... Complete with pictures....

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

Ok, downloaded the manual and looked at pics. Very vague info in that thing.
It was 1Ghz in size. I wrestled with the lower unit trying to get it back in and finally resorted to pulling the outdrive. Wish I had of done this from the onset. It was a snap to get in. Now to cable adjustment. Once again the manual is vague. Anyone ever done from the motor to the drive, and from the control to the motor? Any tips would be apppreciated.

 

[Fishermark]

Re: Need help with a 1977 Mecruiser 120 I/O

Any tips would be apppreciated.

Don't forget the washer on top of the shift shaft or you will be taking it apart again. Been there - done that myself. :redface:

 

[bigbroncoxlt]

Re: Need help with a 1977 Mecruiser 120 I/O

Don't forget the washer on top of the shift shaft or you will be taking it apart again. Been there - done that myself. :redface:

And I thought I was the only one that had done that. I found out that I left that washer off during my first outing of the season. All the sudden I could not shift my boat from forward, then I bumped the interupt switch which put it into neutral and there I sat. I had to be towed in.

Also don't forget the o-ring at the oil passage...Done that once too.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

Oh, boy I think I am going through the same learning curve as you guys did. I saw a small washer laying on the ground that may just be that one.
Any way to check without pulling it back apart? Like maybe checking the engagement to the shift lever?

 

[Fishermark]

Re: Need help with a 1977 Mecruiser 120 I/O

Raise the outdrive and look at the shift shoe - is it fully up and seated in the upper shift shaft?

 

[Fishermark]

Re: Need help with a 1977 Mecruiser 120 I/O

Here's a pic Ziggy posted awhile back showing how they should mate together. If the "shoe" is too low, you know you forgot the washer.

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

think I am OK! Take a look;

 

[Fishermark]

Re: Need help with a 1977 Mecruiser 120 I/O

Looks good!

 

[rbthntr64]

Re: Need help with a 1977 Mecruiser 120 I/O

Back on this project ;o) Guys, I am having issues. Can not get the starter to crank from key, but will jump at solenoid. Also not getting any spark. Anyone have experience with these Mercruiser's?