Alpha One Gen 2 lower shift shaft bushing replacement.

[Nathan3N]

Hey guys, new to the forum and new to boating. Just pick up a 1992 Mariah Diablo 18’ with the Mercruiser 4.3 and an Alpha One Gen 2. It is leaking gear lube from the lower shift bushing. Enough that sitting in my sloped driveway it runs down the drive. It has been checked and confirmed that the shift bushing is the source of the leak. So I ordered a new assembly with the shift bushing and speedometer connection and it is arriving today. Has anybody changed one and what advice can you give? I have searched extensively online and on the forum and cannot find images or video of the process.

At this point I have unbolted and removed the lower section of the drive assembly and have been hesitant to loosen the two bolts holding the bushing assembly in place. Everywhere I look people are saying to be careful and don’t mess up or the whole unit will need rebuilt. I’m looking for any info on this fix and any insight into how to go about it correctly.

 

[Stinnett21]

I did this job this past winter. I found exactly how to do it on the MarineEngine forum. Poster's name was Kghost. He is/was a tech and went through it step by step. It was very easy as long as you follow the instructions exactly. I don't have the date/thread memorized. You'll have to search for it. I hope this doesn't put me in trouble with the iboats gods lol.

 

[Nathan3N]

Thanks Stinnett. I’ll look it up!

 

[Nathan3N]

Haven’t been able to find the post you referenced yet but found many of his others. Do you remember any particulars about the job? Really just don’t wanna mess this up.

 

[Kubaat3lover]

Hi,
most probably I will need to do this, I have bought the seals for 8$ so its cheap and maybe worth to replace during winter
I cannot find it too...

 

[Stinnett21]

Can't find it either now. Bottom line, put it in forward gear, i.e. shift shaft facing forward at 12:00 o'clock, loosen the two screws holding the base and PULL STRAIGHT UP, all the way out. You want to avoid any shaking or moving of the drive unit because doing so could dislodge the shift crank. If that happens you're screwed. So install the new bushing, grease the splines and the shaft, position over the opening and push straight down engaging the splines of the shift crank. This is from memory. Please do your own research. I may be missing something.

 

[cchamp]

I did this about a month ago with no instruction and regretted the hell out of it. The bushing comes off over the metal shift shaft mechanism and mine did not release easily. When removing it I lifted it a bit and then set it back down...and when it went back in forward gear it did not put the shift shaft facing 12:00. Scared the ever loving **** out of me. I was able to re-seat it in the proper position, but for a second I thought I was in major trouble. Take your time and try to find a video (AKA, don't be like me). I think you basically need to use one hand to hold the shift shaft in the position its in and the other to remove the bushing carefully. Definitely do not pull up on the bushing without something securing the shift mechanism. Everything else about the replacement is super easy. Its just a couple of screws.

 

[Bt Doctur]

support the lower unit in a verticle position shift into fwd gear , rod in a straight line remove the 2 bolts in the housing gently pry the housing straight up and out remove e clip ,washer pull shaft from cover insert shaft into new cover sealant around the O rings install carefully and be sure when seated the shaft is in a straight line install bolts and pressure test

 

[Kubaat3lover]

Hello, I will drop the bellhousing most probably during the winter and is it worth to replace this seals there?
https://www.youtube.com/watch?v=Qk-5Jw5RZmc

IVe got newer style Bushing, anyone could tell me how to replace it?

take care

 

[Kubaat3lover]

I do apologise, Cant edit my post, ive bought 26-816575A3 seal kit and it includes this orings, can i just change the seals and leave my old housing?

Take care

 

[Bt Doctur]

You can but you still need to remove the cover, pull the shaft, R/R the seal, reinsert shaft,reinstall

 

[Rick Stephens]

If in doubt, might check the manual:
http://boatinfo.no/lib/mercruiser/manuals/mercruiser14.html#/312

 

[Kubaat3lover]

Just unscrew the bushing and remove with shaft? Im sorry English is not my mother language so thats why I would appreciate any extra tips and tricks doing this.Whats the most important during this? not to rotate the shaft?? Thanks

 

[Rick Stephens]

That is all I did. Removed screws, lifted shaft. Replaced housing and seals and C-clip, reinserted shaft same way it came out.