Change impeller on a Johnson 70hp -86?

[andy65]

I have a Johnson 70hp from 1986, engine code: J70TLCDC, and wonder if it might be time to change the impeller. How often should it be replaced?
Is it enough to replace only the impeller, or should I go for the "water pump repair kit"?
How do I replace the impeller, do I need to remove the whole gearcase or is there a short cut?
How do I know if my engine is 49 cid or 56 cid?

 

[tashasdaddy]

Re: Change impeller on a Johnson 70hp -86?

1978-88 were 49cid. i like to do the hole kit #438602. you have to disconnect the shift linkage under the carb. remove all the bolts holding the lower unit. including the one hiding under the trim tab. and the lower will come down fast.

4 screw in the w.p housing,