Cannot reinstall sterndrive.. driving me crazy!

[jeffconnell12]

Hey guys,

I spent 5 hours today attempting to re mount the sterndrive after replacing the coupler. I have a 1975 mercruiser 3.0L 140hp and installed a Sierra 18-2171 coupler.

Basic breakdown of the events
- aligned engine with the standard tool.. found i could never get the alignment tool more than half an inch into the coupler (maybe normal for this motor?) but was confident it was centered considering how far in it went.
- when installing the sterndrive i can just get the unit onto the mounting bolts and nothing more.. i move the driveshaft by spinning the prop (and made sure the gear is aligned) but cant get it to slide any further forward

could the coupler not fit the driveshaft? Could i be doing anything simple wrong..

thanks for any help.. i was REALLY hoping to have it ready for Monday as i had a trip with my old man planned

 

[Bt Doctur]

Why did you replace the coupler? most coupler failures are caused by collapsed rear motor mounts. Simply replacing the coupler does not mean you are lined up. If the tool dose not seat fully, your not aligned correctly.

 

[jeffconnell12]

The coupler blew out on my first trip with the boat. Spun itself free.

I am guessing the engine has to come back out in order to put new mounts/bushings in?

thanks for all the help!

 

[Bondo]

I am guessing the engine has to come back out in order to put new mounts/bushings in?

Ayuh,..... That is correct,.....

 

[Rick Stephens]

The coupler blew out on my first trip with the boat. Spun itself free.

That doesn't really tell us anything. First trip since you purchased it? First trip of the day? Blowing a coupler is a PITA, sorry that you had to go through that. Especially since it can mean needing a tow as well. But figuring out why it blew a coupler is the most important thing here. Possible causes are broken down rear mounts, but also water soaked and rotted transom and or stringer.

If this is a new to you boat, then a lot of things should be looked at before another first trip. The entire maintenance list should be performed. Most boat owners stop doing the regular and needed maintenance long before they sell their boat.

 

[jeffconnell12]

thanks guys - its an aluminum boat with no rot in the small amounts of wood present.

It happened on my first trip out with the boat since purchasing. It actually had the short block rebuilt (heads machined etc) and many other items replaced.

After looking at the bushing kit online i can 100% confirm that i found some of the large washers and springs used in the kit down in the transom well.. not sure if these fell out while someone was working or if they were old parts replaced and just left in the boat.

considering i have a bad coupler and have found parts of the rear mount bushing kit laying around i'm probably best to pull replace and see if that settles things..

At this point i might just bring it to the mechanic as my time is running out to get it sorted!

 

[Bt Doctur]

Well, if you had the old style mount you defintiely need those parts to keep from killing the coupler but who was the last guy to install the drive by pushing it in using a bumper?

 

[Rick Stephens]

thanks guys - its an aluminum boat with no rot in the small amounts of wood present.

It happened on my first trip out with the boat since purchasing. It actually had the short block rebuilt (heads machined etc) and many other items replaced.

After looking at the bushing kit online i can 100% confirm that i found some of the large washers and springs used in the kit down in the transom well.. not sure if these fell out while someone was working or if they were old parts replaced and just left in the boat.

considering i have a bad coupler and have found parts of the rear mount bushing kit laying around i'm probably best to pull replace and see if that settles things..

At this point i might just bring it to the mechanic as my time is running out to get it sorted!

The hard part will be getting any parts that are missing in hand quickly enough to satisfy your time frame. Not mechanically hard once the motor is hanging. Don't really need to pull the motor all the way, just far enough to set up rear mounting hardware.

Being an aluminum boat with minimal wood REALLY simplifies the rot issues

If you are going to work on this boat, repairs or maintenance, you need the correct Mercruiser manual for your drive. Either download one or purchase one. There are a lot of different sources. You can also use boatinfo.no for viewing the manual online.

 

[jeffconnell12]

thanks again all!

I have ordered the service kit for the bushings with all required parts (link: https://bpi.ebasicpower.com/shop/al...ounts/rear-motor-mount-service-kit-mercruiser)

I pulled the motor last night and have no idea how to remove these old bushings. The are rubber bushings inside a metal sleave and beyond stuck. It also seemed obvious that one bushing was sitting lower than the other likely leading to misalignment.

Any advise on the 2 issues below?

1. how to remove these bushings? Do i heat up the rubber and remove it then hacksaw the metal case?
2. how to i reinstall the motor and line up this spring/lock washer? The diagram makes it look like the spring needs to sit on the mount and you somehow drop the engine onto it..? It is labelled "E" in the image.

Thanks!

I've included a photo of the motor mount and the diagram for install.

 

[Bt Doctur]

Using a hot torch, burn/melt the inner sleeve from the rubber, then using the appropriate size socket, and supporting the housing from the bottom drive the socket down to drive out the sleeve I made a tool to install bushings but it can be done with 2 sockets and a threaded rod to draw the new bushing in from the bottom. Install the ring with the flat side up and drive it in until fully seated , then draw the bushing up until seated

Get some contact cement, weatherstrip adhesive, etc and glue down the fibre ring and put the washer inside it