Lower unit wont separate from top.

[Brinkley1970]

Hi all, My boat came partially off trailer and was drug down dirt mountain road about 200 yards before I noticed. It ground the lower inside round part flat exposing the inside. Plus ground my boat halfway through the drain plug hole. I need to replace Lower unit.
1997 Bayliner w/ 4.3l, Alpha 1 Gen2 out drive. "I think". I'm trying to pull the lower off but it wont separate. The back gets some space but front, "boat side" is still solid. I got all the bolts off. 2 in trim tab and the 5 5/8". I read that it may have to be in fwd gear to pull off. That is a problem, I cant move my gear lever forward in boat but can pull it back towards rev. I think maybe something got messed up in the lower locking it up??
Any advise on getting this thing apart?
Also how do I tell if its a gen 2 or 1? I'm pretty sure its a 2 but I'm really lost on what one to order. Can't find a ser o. I wish I could take it a shop but I live very remote area hours from anything.
Thanks for any help

Thomas

 

[Bt Doctur]

Alpha 1 uses nuts, alpha gen ii uses bolts and nuts
one in front, 2 on each side , 1 under the trim tab. You can drop the lower in any gear but to remove the drive it must be in fwd

 

[Brinkley1970]

Alpha 1 uses nuts, alpha gen ii uses bolts and nuts
one in front, 2 on each side , 1 under the trim tab. You can drop the lower in any gear but to remove the drive it must be in fwd

Thanks for the quick reply. It is a gen 2 then. I just tapped it with mallet and got it separated. Can I order any alpha one gen 2 lower or are the specific to drive/engine?

 

[Eric 3.7LX Alpha 1]

You have to order the correct gear ratio drive. They come in different flavors depending on your engine. The 4.3 uses the 1.84 or (1.81 if SEI) gear ratio. You can sometimes get away with a different ratio with a prop change, but if your buying new, no need for that.

 

[Brinkley1970]

Thanks, I seem to have damaged the internal gears on lower . The shifter is jammed in rev wont budge. Is there a way I can tell what gear ratio I have?

 

[Eric 3.7LX Alpha 1]

With the drive serial number. You can find the serial number under the port side decal, see this attached link from the "Adults Only" sticky at the beginning of this forum. https://forums.iboats.com/threads/w...nd-engine-serial-numbers.608167/#post-4434269

 

[flashback]

I thought all the gearing options were in the upper half and the lower was the same..

 

[Brinkley1970]

I thought all the gearing options were in the upper half and the lower was the same..

IDK. But I did find the serial number in engine compartment on cover that sits on top center. Here is a pic. Im looking online now to get info on gear ratio.

 

[flashback]

If you're the first owner then that's probably accurate, ot

 

[rustybronco]

Alpha 1 Gen 2. The ratio should be 1:81
Lower units should be the same except for the 2:40 ratio.

I believe the 2.40 ratio was high altitude??

 

[Brinkley1970]

Thanks for all the help guys. I found a used one with 90 warranty. I'm gonna order it tonight. Or try to.. wife and all. lol

 

[Eric 3.7LX Alpha 1]

I thought all the gearing options were in the upper half and the lower was the same..

For some reason, I took his post as he was changing the whole drive. Now that I read it again, it looks like he just wanted to change the lower half of the drive.

 

[crazy charlie]

Sounds like you got some good info here but I have to ask.....
You noticed your boat came off the trailer after dragging it 2 football
fields???? am I reading this right??

 

[achris]

There were only 2 different ratio gear housings made. The most common has a ratio of 1.62:1, (the other being 2.00:1) and different drive shaft housing ratios changed the overall ratio. So if you wanted a 1.81:1 overall, you'd used the 1.62 lower and a 1:12:1 upper. For your drive (1.62:1 overall), the top ratio is 1:1, but you don't need to know any of that. You are looking for a standard gear housing. You could even buy a complete drive and as long as it wasn't 2.00:1 or 2.4:1, you'd have the right lower...

iboats sell them...

Sierra Complete Lower Unit Assembly - 18-2400

Additional Details:For Ratios: 1:47:1. 1:62:1, 1:82:1, 1:94:1Fits: Gen II (1998 & Up) s/n 0L100040 & UpUse With:18-2331: Drive Shaft18-2415: Gear Housing AssemblyCross ReferencesMercruiser Stern Drive1623-815822A321623-815822A431623-815822A51623-815822A53Fitment InformationMercruiserALPHA ONE...

www.iboats.com

 

[rustybronco]

His drive shows as a 1997 unit.

 

[achris]

His drive shows as a 1997 unit.

Model number: 5010162KS
Ratio: 1.62:1

Chris....

 

[rustybronco]

The Seirra link shown is for 1998 up.

 

[achris]

The Seirra link shown is for 1998 up.

Same drive from 1991 to current. A few internal changes, but as an assembly, completely interchangeable.

 

[rustybronco]

Understood on the units interchangability but somewhere down the road it may need repairs, The reason for my stating it was a 97.

Thanks for all you do Chris.