2003 DF140 Lower Unit Compatibility

[toddhlynch]

I own a 2003 DF140 and need to replace my lower unit.

I have been offered a 2007 DF115 Lower unit in perfect shape. I have searched endlessly, and I know that the gear ratio is different, but cannot tell if they are interchangeable or what would be required to use it.

Thanks,
Todd

[toddhlynch]

When I look up the gearcase for my outboard:

>>> https://www.boats.net/product/suzuki/55110-92J00-0EP

And look in the compatible list, I see: 11501F-780001, which is the 2007 DF115, making me think the gearcase it the same for both engines

And the same for the Shaft Assembly:

>>> https://www.boats.net/product/suzuki/57110-90J30

It is also compatible with the 11501F-780001

[Solarman]

If you look up your gear case part# online and click on it, you should be able to scroll down to see all of the models/motors that part was used on? Can also do the same with the '07 DF 115 gear case.

Good luck.

[catacom225]

Need to determine the length, 20'' or 25", the drive shaft will be different

[Solarman]

If you are swapping your complete gears, drive shaft, and shifting components you need to check that all parts in your lower unit gear case will change over to the replacement case. Depending on the age and hours of the motors, any worn parts should be replaced.

Good luck.

[toddhlynch]

They are both 25" engines, so the shafts should match.

I know the gear ratio is different between the 140 and 115, so some internal parts are definitely different between the two, but from what I see, the gear casing and the shaft are the same, so I would expect it to bolt on.

Can anyone help me confirm this?

[Murray]

Going out on a limb here because I have no idea the answer to your question. Depending upon the gear ratio difference would you have to over rev the engine to maintain the same speed you were achieving before lower unit replacement, conversely would you be lugging the engine to get to the same speed? If there is any merit to my question would it be as simple as finding a suitable prop? Basically I’m wondering whats going to happen at WOT?

[toddhlynch]

Murray -- my understanding is that if you adjust the prop accordingly then it makes up properly for the different ratio.

Solarman -- I was hoping to swap the whole lower unit.

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So... bad news. I went ahead and had the lower unit shipped to me, and it does not appear to be a match. My mechanic wrote:

We got into the lower unit that you brought to us, however, the lower unit is wrong and does not match up to the previous model. I think they must have a 90 HP lower there because the drive shaft is substantially smaller than yours.

------

This does not make sense to me, the shaft should be identical according to what I looked up. I am working on getting the serial number of the replacement lower unit so I can do an exact lookup, but does anyone have any ideas where I went wrong?

[Solarman]

I think you got the gear case # 55100-90803-0EP

which does fit an 07 df115, but won't fit your motor dt140. If you had gotten your part # gear case, it does fit the 2007 df115Z.

You just didn't get the DF 115 Z gear case.

If you got the gear case through a reputable dealer? They might be willing to swap it for the right one? If available?

Good luck with this.