Lower Unit compatibility question

[Steve75x]

2002 Sea ray 185 v6 4.3 with Alpha One Gen 2

I hit a rock or concrete and it cracked the front of the nose of the gear case as in a hole leaking gear oil out. I was only about 5 minutes from the dock so we headed back. boat actually ran good and got on plane nice and smooth so i was hopeful that the damage was none or minimal. Unfortunately the damage is pretty severe to the case.

I found a lower unit on ebay and seller says it is from a slightly newer boat but with a 1.62 gear ratio. his reason for selling is he said the motor went bad and he is scrapping the rest of the parts. says the lower unit is in good shape. looking at pictures it seems to be very clean with hardly any corrosion. looks to be fresh water use only.

Any thoughts to whether this lower unit would work with mine? anything else I should be on the lookout for? Chances that my upper unit is ok since it ran good back to dock and was only run the time needed to get it back on the trailer? I'm estimating no more than five maybe 10 minutes max running with an engine stop in the middle while it was docked and I got the trailer in the water.

Thank you in advance for any advice or thoughts.

Sincerely,

Steve

 

[Bondo]

Ayuh,...... Welcome Aboard,...... What motor do you have,..??..??

Are you lookin' to swap Just the lower unit, or the entire outdrive,..??
Gear ratio is determined by the upper unit, not the lower,......

The lower unit should run just fine, on yer ole upper unit,.....

 

[isaacs]

2002 Sea ray 185 v6 4.3 with Alpha One Gen 2

I hit a rock or concrete and it cracked the front of the nose of the gear case as in a hole leaking gear oil out. I was only about 5 minutes from the dock so we headed back. boat actually ran good and got on plane nice and smooth so i was hopeful that the damage was none or minimal. Unfortunately the damage is pretty severe to the case.

I found a lower unit on ebay and seller says it is from a slightly newer boat but with a 1.62 gear ratio. his reason for selling is he said the motor went bad and he is scrapping the rest of the parts. says the lower unit is in good shape. looking at pictures it seems to be very clean with hardly any corrosion. looks to be fresh water use only.

Any thoughts to whether this lower unit would work with mine? anything else I should be on the lookout for? Chances that my upper unit is ok since it ran good back to dock and was only run the time needed to get it back on the trailer? I'm estimating no more than five maybe 10 minutes max running with an engine stop in the middle while it was docked and I got the trailer in the water.

Thank you in advance for any advice or thoughts.

Sincerely,

Steve

If it's running smoothly, it probably means there's nothing wrong on the inside--it just can't hold gear oil. Have you thought of patching it with MarineTex? Grind a nice clean slot along the crack and go for it--can't hurt to try and you would save a lot of money!

 

[Steve75x]

The engine is a 4.3 v6. The air cleaner cover says 4.3 Litre Thunderbolt V Ignition Mercury Mercruiser. The engine serial number box is well worn and I can't quite make out what the serial number of any of the units are. The stickers I guess didn't hold up over time.

My thought was to just swap the lower unit and hopefully that is all that's wrong. I'm just worried about throwing $450 on a lower unit from ebay only to find out it isn't compatible or doesn't work for whatever odd reason.

I was also looking at an SEI replacement but they are running almost $900 and it seems some people online are saying the gears and internals just don't hold up.

 

[Steve75x]

If it's running smoothly, it probably means there's nothing wrong on the inside--it just can't hold gear oil. Have you thought of patching it with MarineTex? Grind a nice clean slot along the crack and go for it--can't hurt to try and you would save a lot of money!

Interesting idea, no I hadn't thought of trying to patch it

 

[achris]

Interesting idea, no I hadn't thought of trying to patch it

DON'T try to patch it. With heating and cooling the patch will quickly fall out and you'll lose all the oil again.

If you're going to 'repair' it, get it welded. Which will mean stripping it completely and handing an empty housing to the welder. Probably cheaper and safer to buy that second hand unit and bolt it up. Just make sure it's newer than 1991. (yours is an Alpha One Gen II, in 1991 Merc updated them from the Alpha One, and they are NOT compatible).

Chris.......

 

[nola mike]

What pitch prop do you have on there now?

 

[Steve75x]

DON'T try to patch it. With heating and cooling the patch will quickly fall out and you'll lose all the oil again.

If you're going to 'repair' it, get it welded. Which will mean stripping it completely and handing an empty housing to the welder. Probably cheaper and safer to buy that second hand unit and bolt it up. Just make sure it's newer than 1991. (yours is an Alpha One Gen II, in 1991 Merc updated them from the Alpha One, and they are NOT compatible).

Chris......

ya I think patching it successfully is beyond my skill level, I’m going to look for a used one to bolt up to it

 

[Steve75x]

What pitch prop do you have on there now?

It’s a 19

 

[nola mike]

Assuming you're coming from a 1.84 drive, you'll probably need to reprop. You should have some wiggle room if you have a 19 now

 

[achris]

Assuming you're coming from a 1.84 drive, you'll probably need to reprop. You should have some wiggle room if you have a 19 now

NEGATIVE!

If replacing just the lower, the gear tooth count is the same, regardless of engine. They are ALL 13:21. Ratio differences are effected in the UPPER housing, not the lower.

If he's running a 19" prop now, a change to a new lower will see a 19" still being the right prop.

Chris.......

 

[nola mike]

NEGATIVE!

If replacing just the lower, the gear tooth count is the same, regardless of engine. They are ALL 13:21. Ratio differences are effected in the UPPER housing, not the lower.

If he's running a 19" prop now, a change to a new lower will see a 19" still being the right prop.

Chris.......

He never responded to @Bondo about what exactly he was replacing, if "lower" meant "stern drive" then he'll need to reprop. And since he specified the gear ratio...
$250 gets me complete out drives around here. I'd be wary of just buying the lower anyway for fear of what happened to the upper.

 

[achris]

He never responded to @Bondo about what exactly he was replacing, if "lower" meant "stern drive" ....

Read Bondo's question in post #2, and the OP's response in post #4.....

'lower' means gear housing, not entire drive...

 

[nola mike]

Read Bondo's question in post #2, and the OP's response in post #4.....

'lower' means gear housing, not entire drive...

As long as the op knows the difference. People will frequently say "lower unit" when talking about the entire drive.