shifting probs on a 1972 mercruiser 120 hp

mojoeseeka

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Joined
Jul 13, 2004
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2
Could anybody help me with my problem...I recently purchased a used 18 ft starcraft deep "V"<br />with the above mentiond merc 120 hp 2.5L GM 153 cid well i was having heating probs and reading the posts on this site gave me the info i needed to cure that but at first i took apart the lower unit to inspect things and didnt realize that the impeller that currently was in there was junk(i just didnt see no broken flaps so i thought it was good.....IDOIT!!!LOL)so i put it back together thinking everything was good....got about 4 or 5 hours out of it when putting it in to reverse one time it started to "clunk countinously while trying to put it in i would rev it up some thinking it was just quite getting all the way in continued to do this so the next weekend i took it apart again finding out then that my impeller was bad....i dropped the lower unit again to fix the impeller and try to see if i had that brass shift dog seated correcdtly to that little shift spline right in front of the main shaft...i began by taking it for ride the temp was now great!! i now need a thermosat.and it went into forward fine but bringing it back to neutral was REALLY hard and hard to find it too almost like i had to go into reverse to have it fall into neutral and revese did the same thing as before a consant clunking i rev it and falls in and it then goes into revese not a sound being made out of it once into gear and i can go pretty good in revese seein if at high speed it would make any noise and it didnt....then me and my 1st mate started to mess with control box cables to shift plate and also lower gear cable outdrive when doing it manually with drive cable prop shaft locks when going counterclockwise and pushing in on drive cable and then when going clockwise and have him pull outward with drive cable i kinda hear a slipping noise in lower unit it could be me but i think its that brass leg that is in the upper unit that slides over the spline in the lower unit is there some sort of allignment to use to make sure thats right?i know this is a bit long winded but i would sure apprecaite the help!This fgorum has already been a big help and has saved me some money!
 

mojoeseeka

Recruit
Joined
Jul 13, 2004
Messages
2
Re: shifting probs on a 1972 mercruiser 120 hp

thnx for the response guys! but this is where im at with the process of shifting re-installation: 7. Move the control lever to the full reverse position, as the helper turns the prop slowly clockwise unitl it stops here my prop shaft will never "LOCK" into place it keeps skipping over feel it almost catching but not quite,foward goes right in i got the measurements right 5 7/8" for my 1972 (pre 74)i also got a slot for my post to connect cable ends should that be bottomed out to the bottom or middle of slot?again thnx for help guys :)
 
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