Short to Long Shaft Swap

[frogtog]

I've seen some topics related to this but not exactly answering my problem.

I have a late 60's Johnson/Evinrude 6 hp LONG shaft outboard. I'm looking into "transferring" or swapping the lower unit to a a less used same year short shaft. I am wondering how involved of a project it is.

Thanks.

 

[oldboat1]

It's an easy project -- have to cut 5 inches off the water tube (or replace the long tube with a short one). You need the shorter driveshaft, which is presumably in the replacement unit. Housing extension is removed, of course. Keep it and the long driveshaft for possible conversion back to a long shaft.

 

[frogtog]

It's an easy project -- have to cut 5 inches off the water tube (or replace the long tube with a short one). You need the shorter driveshaft, which is presumably in the replacement unit.

Thank you for the response. Not sure if I was being clear but I want to keep the extended or longer lower unit. What I mean is removing the lower unit of the long shaft and transferring it to the short shaft.

 

[F_R]

Lower unit (gearcase) is the same, long or short shaft. What makes the difference is the 5" extension housing, shift rod, drive shaft, and water tube.

Not all years are the same.

 

[frogtog]

Lower unit (gearcase) is the same, long or short shaft. What makes the difference is the 5" extension housing, shift rod, drive shaft, and water tube.

Not all years are the same.

I see what you mean. I have never taken a lower unit out nor an extension. if I disconnect it at the top part of the extension, is it just a matter of bolting the extension/lower unit to the other shaft?

Model No 6RL-69M

 

[oldboat1]

I think you would disconnect at the bottom of the extension, if keeping the long shaft. That shift rod probably has the extended (5") brass connector, and I think you would disconnect that at the bottom bolt.

 

[F_R]

Well, I just looked at two parts books for 1969.

One book shows a part number 311381 for a short shaft upper shift rod, and the other shows a 311382 for a long shaft upper shift rod.

The other book shows a 311381 for both short and/or long shaft, with the conversion by a standard or extra-long shift rod connector joining the upper and lower rods.

So...My bet is the first book is correct, and the long shaft motor has a 5" longer 311382 upper shift rod (because that was the cheaper way to manufacture it). If that is correct, you have to remove the powerhead to replace the upper shift rod with a 311381 if converting long to short. On the other hand, if you are converting short to long, simply use a 5" longer connector.

To make all this make more sense, remove the lower unit gearcase and see if you have a long or short shift rod connector, and go from there.

 

[racerone]

There is a wee clip above the pinion gear and both lower units may need to come apart to get the shafts out.-----And the easy fix would be to switch the power heads.-------New water pump impeller while power head is off is recommended too !

 

[GA_Boater]

Wouldn't be easier to swap out the current long shaft powerhead for the less used short shaft powerhead?

Hey - Welcome aboard, Frog.

 

[F_R]

There is a wee clip above the pinion gear and both lower units may need to come apart to get the shafts out.-----And the easy fix would be to switch the power heads.-------New water pump impeller while power head is off is recommended too !

Service manual sez the drive shaft will come out after removing water pump, no need to take gearcase apart to get it out.

 

[frogtog]

I'm not sure about all the shaft parts terminology but I called my local boat shop and they said that its just a matter of unbolting the long shaft extension carefully, sliding out the drive shaft, insert it to the "newer" short shaft taking care that shaft splines go in properly.

 

[Roberthill]

Raised one of these motors years ago by bolting a 2" by 12" board on the transom . Just a suggestion .

 

[racerone]

frogtog-------But there is no spline on the bottom of a factory original driveshaft !!------There is a key and a clip ( item 10 ) that need to be looked at.