Replacing impeller on old Johnson AD-12 7.5 hp

[schaaed1]

Any insight to replacing an impeller on an old ('58) Johnson AD-12 7.5 horse? Are there any tricks or complications with this relic that one would not expect with a more modern unit?

Thanks,
Ed

[TONGA]

pretty strait forward

[schaaed1]

Replaced with out too much agrivation ... once I realized I had to remove the power head, to get to be able to disconnect the shift linkage. the only place to break this connection is at the end of the shift arm. All the other impellers I've changed have been on larger OB's. So, not sure if most of the smaller OB's are this way or not.

Another question though ... in its day this motor called for 25:1 of non detergent 30 weight oil. With today's improvements in 2-cycle oil, should I still be running 25:1? or somewhere between 25:1 and 50:1.

Thanks,
Ed

[outdoorsman69]

stick with the 24:1` that motor has bronze bushings rather than roller or cage bearings. extra lubrication never hurt any motor ;)

DCG

[schaaed1]

Thanks for the bearing info DCG! I did not realize that they had bronze bushings. I'll stick with the original mixture ... that way I won't need to use any 'Deep Woods Off' when I'm out trolling. ;) In all honestly though, it isn't that much worse than many 50:1 OB's.

Ed