Trouble re-mounting lower unit

[craig newton]

I have a 96 Mercruiser 4.3LX Vortec 4BB Alpha one Gen two. I dropped the lower unit and installed a new water pump kit. I've done this a number of times with a gen one and never had any real trouble doing it without help. This is my first gen two. I put it in forward when I dropped it and made sure the shift shaft was in forward putting it back. Since I don't have help I use a floor jack to lift it into position. At first I had trouble lining it up straight and the front bolt would start to go in on an angle, get stuck and prevent me from lining up the rest of the holes. I re-positioned the jack and got past that and was able to get it almost all the way in leaving an even gap all the way around slightly less than 1/2". Just enough so I can't get a nut on the mounting bolts. So I put two bolts in that are 1/2" longer to hold it in place, removed the jack and trimmed down to horizontal position hoping to use those bolts to raise it up enough to put the original bolts back in. With less than 1/2" to go, I would think the spine has engaged correctly and all the holes are lined up straight but something is stopping it from completely closing up.

 

[Scott06]

I have a 96 Mercruiser 4.3LX Vortec 4BB Alpha one Gen two. I dropped the lower unit and installed a new water pump kit. I've done this a number of times with a gen one and never had any real trouble doing it without help. This is my first gen two. I put it in forward when I dropped it and made sure the shift shaft was in forward putting it back. Since I don't have help I use a floor jack to lift it into position. At first I had trouble lining it up straight and the front bolt would start to go in on an angle, get stuck and prevent me from lining up the rest of the holes. I re-positioned the jack and got past that and was able to get it almost all the way in leaving an even gap all the way around slightly less than 1/2". Just enough so I can't get a nut on the mounting bolts. So I put two bolts in that are 1/2" longer to hold it in place, removed the jack and trimmed down to horizontal position hoping to use those bolts to raise it up enough to put the original bolts back in. With less than 1/2" to go, I would think the spine has engaged correctly and all the holes are lined up straight but something is stopping it from completely closing up.

wonder of the water tube is misaligned - the one that comes up from water pump to underside of upper.

also think that with 1/2" the splines are lined up. With it in gear you can confirm this by turning the input or prop shaft they will turn together if splines are in place.

 

[Bt Doctur]

the easiest way is to place the lower in a stand using some 2 x 4`s and installing the upper on it , them remount the whole drive.
Theres way too much risk trying to force it to fit

 

[craig newton]

Thank you. That's what I am going to do next year. I already built a stand for the lower unit. I'm thinking I may just drop the lower again and pull the upper instead of trying to re-mount it again. Turns out my water tube came off. I dropped it half a dozen times and thought I had it this time. Thanks again.

 

[craig newton]

wonder of the water tube is misaligned - the one that comes up from water pump to underside of upper.

also think that with 1/2" the splines are lined up. With it in gear you can confirm this by turning the input or prop shaft they will turn together if splines are in place.

Thank you Scott06. You nailed it. I had so much trouble keeping that water tube attached let alone aligned.

 

[Bt Doctur]

try using 3M weathersrtip on the plastic tube to hold it in place.