Replace 2002 115hp lower unit

[sr79]

When shifting into reverse it makes a short gear grinding noise and sounds noisy when running with water muffs but works okay. I suspect reverse lugs are worn or something like that. I have an opportunity to buy a 2007 lower in good condition, the only thing I see different is length of shift shaft, mine is about 6" long and the 2007 is much shorter. My question is: is it possible to install a longer shift shaft in the 2007 lower gear case? Thanks for any advise. Dennis

 

[Chris1956]

Driveshafts are the same length?

Merc may make an extension for the shift shaft, I am not sure. I know they make extensions for the driveshafts, as part of the kits to create a 25" shaft from a 20" shaft. These have bolt on Midsection extension, driveshaft extension, longer studs, water tube extension.

 

[racerone]

Granny shifting ( easing into gear ) is bad for a gearcase.-----So shift with a quick motion.----Perhaps adjust shift cable.---I do not think you have to replace this unit !!

 

[sr79]

Driveshafts are the same length?

Merc may make an extension for the shift shaft, I am not sure. I know they make extensions for the driveshafts, as part of the kits to create a 25" shaft from a 20" shaft. These have bolt on Midsection extension, driveshaft extension, longer studs, water tube extension.

Thank you, I will check into shift shaft extension possibility.

 

[sr79]

Granny shifting ( easing into gear ) is bad for a gearcase.-----So shift with a quick motion.----Perhaps adjust shift cable.---I do not think you have to replace this unit !!

Thank you, I do try to shift quickly.

 

[sr79]

Thank you, I will check into shift shaft extension possibility.

Does anyone know where I might get a shift shaft extension?

 

[flyingscott]

Are you sure a 2007 lower will fit on your motor? Should make sure before you spend the money. Not all 115s are the same.

 

[sr79]

Are you sure a 2007 lower will fit on your motor? Should make sure before you spend the money. Not all 115s are the same.

I know a 2007 "as is" will not fit on a 2002 without some or major modifications - if that's even possible. Thx

 

[Faztbullet]

All the metric lower units will interchange. Only difference is ratio and clutches. You can put a 1987 unit on a 2007 if you have the correct linkages to make shift throw length correct and shift shaft. Around 1997 Merc went from a 3 jaw to 6 jaw clutch and the throw length is different. Also in 2006 there was a change in shift shaft lengths it was either a 7/8 stub or a 5-7/8 stub. So yes it doable

 

[sr79]

All the metric lower units will interchange. Only difference is ratio and clutches. You can put a 1987 unit on a 2007 if you have the correct linkages to make shift throw length correct and shift shaft. Around 1997 Merc went from a 3 jaw to 6 jaw clutch and the throw length is different. Also in 2006 there was a change in shift shaft lengths it was either a 7/8 stub or a 5-7/8 stub. So yes it doable

Thank you, very interesting information and does that mean I can take the parts out of my 2002 lower and put them into a 2007 lower gear case? Are 2002 and 2007 gear cases exactly the same and interchangeable?

 

[Texasmark]

The lower unit with the 6 toothed R gear is identified with a casting change: Get behind the engine facing forward and look down at the center, rear of the LU, the raised area that extends to the rear of the unit. In the casting, about 2" from the rear end is a diagonal in the casting whereby previous 3 tooth had this part of the casting straight across....per the service manual for models including my 2002 115.