50 hp Johnson (1971) NO Reverse

[jonb_in_MN]

I am a new first time boat owner.<br />My '71 Johnson 50 hp starts great and runs smooth.<br />BUT... when shifted into reverse, it goes forward. Also when shifted in forward I only have about half power (my 14' aluminum runabout won't plain out).<br /><br />This has the Hydro-Electric shift. I understand it needs a special type C gearcase oil. the dark black thick oil I drained out of my gearcase smelled strong, I figure it's 80-90 weight. I put in the correct OMC gearcase oil last night.<br />The questions are:<br />Is this going to correct my problems?<br />Did that 80-90 oil do any damage to the Hydraulic pump or anything else?<br />What else should I do before running it again?<br /><br />any input is appreciated<br />Jon