Mercruiser Lower Unit Won't Go Back In!!!

[matty44789]

Hello everyone,
I recently obtained a 1986 stingray mercruiser 120 Alpha One. Anyways i had to change the impellar in it since it was ripped to tiny pieces of rubber. Guess because it was started out of the water. So i replaced it, put the water pump back together now when i try to put the lower unit back in it wont go all the way back in. I lined up the gearing for it and tried putting it in forward/Neutral nothing works. It feels like it's hitting the top of the inside shaft and wont go all the way into the threads. It sticks about about an inch. Its definetly hitting the top. Help please!!!!

 

[Don S]

Re: Mercruiser Lower Unit Won't Go Back In!!!

That is why it's best for first timers to take the drive completely off the boat to do the impeller.
Now, all you have to do is hold the drive up, line up the cooling tube, line up the shifter (in forward) and turn the prop CCW to line up the splines. All at the same time.
Oh, and don't bump that new quad ring around the oil passage out of possition

 

[kewlkatdady]

Re: Mercruiser Lower Unit Won't Go Back In!!!

well I just did this for the first time today...
I struggled with it for about 30 mins...

I had the rigid black tube on the lower unit. I couldn't get them lined up....

Took the black tube off the lower unit and put it in the upper unit...

went right on.

Mine is an alpha 1 gen 2.

Good luck.

 

[Augoose]

Re: Mercruiser Lower Unit Won't Go Back In!!!

Also ensure you lube up those splines on the vertical shaft (but not the tip top of the shaft) and the water tube itself. In the picture, I see no grease at all.

Like Don said, ensure the gear unit end of the shift shaft coupler is straight forward (ie, in forward gear) while at the same time, rotating the prop shaft (or prop if you forgot to take it off) counter-clockwise until the prop locks in and the shift shaft coupler is facing straight ahead- then keep holding the prop with a bungee cord or find a helper. Start putting the components together and turn the upper drive shaft a little bit to help the vertical shaft from the lower gear unit line up with the driven gear in the upper unit.
Jiggle it like mad and it will go together. You just need to line up the teeth.

 

[sabastianunf]

Re: Mercruiser Lower Unit Won't Go Back In!!!

The first time I pulled my lower unit I had the same problem. There is a rubber seal that goes around the outlet tube from the water pump that was stuck in the top half of the outdrive. I used a seal puller to pop it out and then put it on the outlet tube for the water pump then reassymbled with out any problem.

 

[ziggy]

Re: Mercruiser Lower Unit Won't Go Back In!!!

That is why it's best for first timers to take the drive completely off the boat to do the impeller.

it's a good idea for folks that've done an impeller a few times too.
i've been plenty pained over putting the lower back while the upper was still on the boat too. real pained. i've not done that for a while though. once yer hip to doing it on the bench. it's like a 1st try thing. ya just slide them together, no muss, no fuss. so much easier it's not even funny.

 

[wpg manitoba]

Re: Mercruiser Lower Unit Won't Go Back In!!!

I had this exact problem with my mariner yesterday. Took me an hour to finally get it to in. I felt concerned at one point when I noticed metal shaving on the spline from spinning the propeller. Wiped it off put some more oil and it finally went in. I hope it will still be okay though.

 

[greekfreek]

Re: Mercruiser Lower Unit Won't Go Back In!!!

So its much easier to put the two halves together on the bench ?? Laying them down???

 

[ktbarrentine]

Re: Mercruiser Lower Unit Won't Go Back In!!!

My workbench is configured to work on the drive vertically. I find it easier that way. Mount the lower in the bench, and then lower the upper onto the lower, looking into the exhaust passage to get a good view of what's going on. I've also heard some people do it upside down.

 

[cpt ron jc]

Re: Mercruiser Lower Unit Won't Go Back In!!!

just changed my impeller last week ,just removed the lower, 6 bolts it slides right off ,my friend helped me put it back on 2nd shot we got it, another person helps when putting in back on .foward gear always when removeing.

 

[brnschoneck]

Re: Mercruiser Lower Unit Won't Go Back In!!!

yes ive spent 3 hours by myslef trying my second time ,said screw it got some help bammmm went right in ,very hard to do by urslef a helper is always easier ....

 

[slag]

Re: Mercruiser Lower Unit Won't Go Back In!!!

In my experience, it is very easy to get the shift leg slightly twisted when trying to reassemble the two halves. If you make sure the shift leg and lever match up, just slightly turn the propeller CCW and it will all slide together.

 

[cpt ron jc]

Re: Mercruiser Lower Unit Won't Go Back In!!!

right, once the shaft moves you may have to line it back up by turning the prop counter clock wise,make sure your in forward gear,y can tell if the lower is in gear by turning the prop counter clock wise ,the top shaft will move,i turned mine 1/2 in ,went right back in,2 people makes all the difference,its tough to hold up and turn the prop to line it back if y have to.

 

[greekfreek]

Re: Mercruiser Lower Unit Won't Go Back In!!!

matty44789, did you get it on??

 

[ktbarrentine]

Re: Mercruiser Lower Unit Won't Go Back In!!!

Dang! This thread is OVER 2 years old!!! (I shoulda noticed this before I posted to the thread back up in numbers 7, 8, 9.) I doubt Matty44789 will even answer (this was his one and only post)..... I recommend you: 1. PM him to see if he is still around (good luck with that!!!), and 2. start a new thread if you are having issues with your drive.
Regards,
KB