Need help with a 1975 Mercruiser Outdrive

[mags]

I just bought a boat with what the guy described as a 1975 mercruiser outdrive. That seems to be correct from everything I have looked at online. I actually have two problems the first being that the outdrive will go into neutral and reverse and spin the prop in reverse. However it will not engage into forward gear and I hear a clicking sound coming from the outdrive like it is trying to engage but wont. The guy I bought it from said he was playing with the adjustments on the inside of the boat and then it wouldnt go forward. Any thoughts, is it really just an adjustment issue with the shift lever, or was this guy just selling me that and really the outdrive is broken? Next question is where do you add oil or check the oil for the outdrive at? The next problem is the guy said you dont have to run the lead additive in the fuel if you dont want to. The engine he says is actually a 1974 vega engine that was installed after the 75 went bad. Did mercury use a gm vega engine in their 120HP/2.5L application? And also what are thoughts on using the lead additive for or against?

 

[DGIFF396]

Re: Need help with a 1975 Mercruiser Outdrive

I just asked about checking fluid level today and my out drive is a 78 so if its the same its the port side marked oil vent...level should be within 1/2 of threads bottom when u remove the screw

 

[Bondo]

Re: Need help with a 1975 Mercruiser Outdrive

My 1st Guess is the Lower Shift Cable is Junk,.....

2),..... As noted,... The Oil Level is to the bottom of the Vent Screw......

3),...... Nope,...... No Vega motors were used in Boats.......

 

[mags]

Re: Need help with a 1975 Mercruiser Outdrive

I am going to change the oil in the outdrive. I looked at the shift cable and when you say lower I am assuming you mean the one that runs to the outdrive? The one that runs to the outdrive looks pretty new the one that runs up to the shifter looks kind of old. I have a work order that states a shift cable was changed but does not specify which one I assume it is the newer looking one. Also it says a shift boot gimble and brg-yoke and seal were changed. The plate where the shift cables end has a switch on it that flips when it goes to reverse but stays in place when I put it in forward but it seems like it should switch. It is hooked to some sort of electrical connection that is not hooked up. Is this for a drive light maybe? (Like a light on the dash that would tell you whether you were in forward or reverse?). I appreciate the help this is my first boat and Im pretty excited to get it out on the water so hopefully I can figure this out. Thanks.

Mags

 

[Haut Medoc]

Re: Need help with a 1975 Mercruiser Outdrive

Welcome to iboats.....
No, there is no indicater light......
What you can do to attempt to find the cause is this:
Disconnect the lower shift cable from the shift plate, do not allow the barrel nut to move......
Push the cable inward while you have an assistant turn the prop CCW....
Will it lock into gear?
Measure from the center of the barrel nut to the center of the cable end eye......
It should be 6"......
It is possible that the helm cable is bad.....
Test that by removing it from the shift plate & measuring the travel.....
That measurement should be about 3" if I recall......​

 

[mags]

Re: Need help with a 1975 Mercruiser Outdrive

HA!
I got it to work in forward and reverse. Now I just need to figure out why when I drained the oil it was milky and there was only about 25 oz. when there should be 36................I got a manual and I am going to tear the drive down and replace all the seals. Thanks for the all the help, this drive tear down should be fun. By the time I am done with this thing I will know all there is too know about pre-alpha stern drives. BOAT (Break Out Another Thousand) or at least thats what my buddy says.