Mercury 40 4hp (Gnat)

[pandhsailors]

Hi

i have recently purchased a mercury 40 4HP 2 cylinder Gnat.

Having cleaned the engine thoug, it is now running smoothly again

however I have a problem with the gear shift, I hope some one could help.

The sift lever did go around and around when I bought it, I have taken the head unit off, to find that the pin in the cam had corroded and sheared. this has been replaced. I noticed that the Cam was very worn as though it had been rubbing on the drive shaft.
I put the leg back together. it appears now the engine is stuck in gear if I move the shift arm it does indeed rub on the drive shaft.

I'm obviously going to have to change something so that it does not rub, but even with the leg apart the gear box does not appear to be shifting in and out of gear.

Does anyone know how the lower gear box comes apart or how the "Spring Clutch" should work?
any thoughts would be much appreciated.

[pandhsailors]

the shift rod does move freely in and out of the lower gear box when the leg is dismantled.

[mr-steve-jones]

The shift rod has a flat on the bottom end and it goes against a flat on a spring that wraps around the bottom drive shaft.
When the rod is down, the flat touches the spring and this stops the drive shaft spinning.
If the flat is not aligned, or the spring is snapped, it wont stop the shaft turning.