Re: Mercury 90 3 cyclender
The small wire C-clips can be a pain until you learn the technique for installing them.
A small part of needle-nosed pliers, with the clip opening straight down at the 6 o'clock position, grab the clip at the 9 o'clock.
Tilt the pliers and clip such that the bottom right side of the clip, (the end of the wire) is in the grove cut into the piston pin hole at the 6:30 position.
The trick is to push down and to the right while making a slight CCW rotation with the pliers/clip such that the clip compresses, and you more or less 'roll' the wire into place in the grove, from the first end of the wire clip CCW til it is in so far that your pliers fit into the small 'notch' that is there to ease installing/removing the clip. If the 'notch' is at the 3 o'clock position then reverse these directions.
Edit:
Be SURE, once installed, that the opening in the clip is either straight down, or straight up. If the opening is to either side it WILL eventually fail, inertia will cause the clip to 'spring' at high RPM, lifting the clip end out of position as the piston changes direction (Top and Bottom) each stroke. The continued 'working' of the wire will cause failure, the pieces will get out and cause piton/cyl damage as will the pin once it is free to dig a groove and destroy the cyl.
It does take a fair amount of practice.
Be glad they are not spiral-locks, kind of like a flattened keyring.
J