Johnson 9.9 1978 Lower Unit Replacement

[Tom Ross]

Question: I purchased a boat that requires a long shaft motor. I have a 1978 Johnson 9.9 with a short shaft. I purchased a used long shaft lower unit that has the drive shaft and shift rod attached. I have never changed out a lower unit before and need some help in knowing just how to proceed. Will I need to put a new gasket in between the lower unit and the body, and if so can these be purchased or do you make them? Do I need to disconnect the shift rod from the motor before trying to attach the lower unit? What do I do with the shift rod to make sure the gears will work correctly once it is installed? Any other details that I am missing, or suggestions will be greatly appreciated.

 

[Alby1]

Re: Johnson 9.9 1978 Lower Unit Replacement

You can buy the gasket a NAPA for about $2.50. But....you don't need to remove the whole housing. Just take the guts out of the long shaft and install them in you existing housing. That consist of Drive shaft, extension housing and water pump tube guide, the lower shift rod and lower unit. The shift rod comes apart about half way down the housing. When you unbolt the extension it will drop down about 3/4". Use a screw driver or 7/16 to take the top screw out of the clamp that ties the two rods together. This should all come off in one piece except the tube guide and the extension collar for the drive shaft. When changing out the drive shaft ya have to unbolt the water pump. Check the condition of the impeller before reassemble.
Hope that helps. I suggest you go to the library and check out a service manual. It will save ya bunch of trouble.

 

[Tom Ross]

Re: Johnson 9.9 1978 Lower Unit Replacement

Thanks for the advise. I will try to find a service manuel and see if I can get this done.