Evinrude/johnson lower unit measurements

[mav6759]

I just got a lower unit for my boat motor (1989 Evinrude 155hp), but I can't determine if its a 20" or 25". Does anyone know how to measure the lower unit (if I'm saying it right) to determine if it is 20" or 25"..

Thanks Mav

 

[hardwater fisherman]

Re: Evinrude/johnson lower unit measurements

here you go

 

[hardwater fisherman]

Re: Evinrude/johnson lower unit measurements

sorry i may have misread your post do you you have just the gearcase?

 

[daselbee]

Re: Evinrude/johnson lower unit measurements

Measure the length of the driveshaft from the top to the lower unit mating surface (with midsection). If in the range of 27" it is a 25" gearcase. If in the range of 22", then it is a 20" gearcase. Doesn't matter exact numbers....there is a 5" difference, so to determine which one you have, you gotta just know the ballpark.
If you have the wrong one for your motor, it is a real task to swap the driveshafts, by the way.