I have a 64 Johnson Seahorse 6hp, which i mounted on a 1964 12' Starcraft aluminum boat. The motor had not been run in 2 years. I changed the plugs, and put oil in the lower unit, as it was filled with rust colored greasy water. motor runs well, and will really crank up in neutral. But when in gear, under power, it will not plane the boat off. It seems like it just won't open up all the way. i would appreciate any advice.
Hello 67 seahorse,
That is good that you got her running, The bad is you are getting water in the lower unit which is not good, That is what it sounds like from your description rustywater/milky oil. You can get a seal kit to seal the lower unit. As far as the motor goes I suspect the carb main jet could be clogged. I would take the carb off take it apart clean it and get a rebuild kit if moneys allow. And also get a tune-up/points/condenser kit if your not sure the last time a complete tune-up was done.. And reseal that lower unit if the oil gets milky again keep a close eye on that. Hope this helps and gives you some insight. Any questions PM me. John