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1998 2-stroke 8HP Mercury (plastic) shift pulley/gear problem noted

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whitegreg56

Regular Contributor
After many years of trouble-free operation (I did all the maintenance) it developed shifting problems. It is a tiller-handle shift. I thought it was in the gear case so I removed the lower unit and found it was OK. Finally replaced the plastic shift/throttle pulley and plastic shift gear (it's hardly a gear...but they call it that) and the problem is history. I cleaned the grease off the old parts and they look fine....no cracks or apparent wear. I'm left wondering what's going on. Has anybody seen this? Looking forward to another good season!
 
If you are talking about the gear (#2) itself (starboard side of the motor with the linkage from the shifter attached), I have never seen that fail (and I work on alot of these motors - 6/8/9.9/15's).

If you are talking about the little cam (#31) that the shift shaft connects to (Merc calls that a "lever" which is operated by a rod from that "gear"), I have seen a few of those fail - but in all cases it was apparently due to a failure of the little spring (#35 - piece of spring steel) that keeps the linkage "in gear".

I am interested in knowing what failed here - can you pick out what you changed from the diagram attached.
 

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  • linkage - small Merc.jpg
    linkage - small Merc.jpg
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I replaced parts 2 and 3 (they even came together). I came within a hair of buying a new engine. I noticed that if I put pressure on the shift link rod (part 33) while shifting, parts 2 and 3 would bind. Still don't know why. This story has a good ending.....I put it all back together....put it in the test tank....it shifts like new. May get a few more years out of it.
 
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