Installing a new 4.3 Mercruiser

[Bruce 2nd]

Good morning folks! With everyone’s help I’ve been told to get a new 4.3 mercruiser and that’s what I’m doing. I’m also replacing the risers, manifolds and shutters as recommended to avoid future hydrolock. My question is I’ve taken the motor out without removing the lower unit. Is it possible to reinstall the motor this way or is it damn near impossible to get the shaft to slide in and be realigned when lowering it back in.

 

[JASinIL2006]

I'm surprised you were able to get the old motor out without pulling the drive...

Yes, pull the drive. It has to be off anyway so you can check alignment after dropping in the new motor.

 

[nola mike]

Don't know how the hell you got it out, but you absolutely need to remove the lower unit. For many reasons, including engine alignment, inspection, and of course just installation.

 

[Bruce 2nd]

It was quite simple. Once all the bolts were out I lifted the motor slightly and pushed it forward until the shaft fully slid out, then went up and out. Will do thanks for the help. Guess I’ll need to acquire the appropriate tools to check alignment.

 

[nola mike]

It was quite simple. Once all the bolts were out I lifted the motor slightly and pushed it forward until the shaft fully slid out, then went up and out. Will do thanks for the help. Guess I’ll need to acquire the appropriate tools to check alignment.

Pull the drive first, check gimbal bearing. Some of the alignment tools come with a bearing installer as well, might be worth buying.

 

[JASinIL2006]

It was quite simple. Once all the bolts were out I lifted the motor slightly and pushed it forward until the shaft fully slid out, then went up and out. Will do thanks for the help. Guess I’ll need to acquire the appropriate tools to check alignment.

You don't need to buy a Mercruiser alignment tool... many of us have purchased nonbranded alignment bars off EvilBay that work just fine. I think I paid about $38 for mine.

You really should be pulling your drive annually to inspect U-joints, belows and alignment, anyway, so having the tool is just a good idea.

 

[Bruce 2nd]

Thanks for the help gentlemen.

 

[Bruce 2nd]

About to pull this stern drive. It says alpha one on it and it appears to be gen2. Any pointers? Looks like I unhook the 2 hrydos at the back and take 6 bolts out.

 

[Chris51280]

move shift to forward first

 

[Bruce 2nd]

That was easy. I'm sure the fun part is now. What am i looking for? I see no water intrusion. There is oil laying inside the boot I'm guessing that's normal? I'm not seeing any visible cracking in these boots either. No back and forth play in the bearing.

 

[nola mike]

No, not normal. Is it gear oil? You're just looking for smooth rotation of the bearing.

 

[Bruce 2nd]

Bearing feels fine. Looks a little black to be gear oil.

 

[nola mike]

Bearing feels fine. Looks a little black to be gear oil.

How's it smell? No mistaking gear oil from motor oil by smell

 

[Bruce 2nd]

How's it smell? No mistaking gear oil from motor oil by smell

Smells like gear to me but where in the hell would that come from? It's not leaking around the shaft by the ujoints.

 

[Bruce 2nd]

Has to be the shaft seal right? How else would the below be full of oil?

 

[nola mike]

Has to be the shaft seal right? How else would the below be full of oil?

Yeah, input shaft seal. How's the level in the drive?

 

[Bruce 2nd]

Level was full and the oil is clean. I find that odd if some leaked out unless it was over full. Let some out of the bottom to see if any water came out and it was all oil. Water is heavier then oil so I would assume water would of come out first if there were any at the bottom screw. Nice these things have the dip stick in the top to check the level. How does this seal shaft come off? Looks like the cover turns out with threads by the shaft and ujoints.

 

[dubs283]

pressure test will show if the seal is sound, need to rotate input shaft while under pressure to simulate running drive

yoke seal is removed by disassembling the drive shaft assy/bearing pack. remove drivshaft assy by removing retainer at yoke input, best achieved with the special tool which is required for installation in order to provide the proper torque

 

[Chris51280]

I had the same issue. change the seal. then it was all dry inside. if the yoke is too worn with grooves, get a speedy sleeve. You have it all apart at that point, so change the other seals too. Once you change the yoke seal, the u-joints are easy to replace. cross reference to automotive and they are about $15 a piece