Knocking noise, could it be fouled propeller? Help

[adhdan]

I assume you are planning on removing the rope cutter completely. When I serviced mine it was done with the boat on the hard. The cutter rotates with the shaft and the fixed blade er doesn’t. The nylon washers are there to give clearance to the rotary blade.The service kit was just nylon washers and Allen bolts. I wouldn’t try refitting under water. I can’t be see worn washers causing a noise although a damaged cutter would. The clearance between the fixed and rotary blade is only about 3 mm

yeh my plan was too unbolt the 2 allen bolts on the fixed blade and remove it & then the boat is usable again but the blade came out of the V groove and was banging around like crazy, happened maybe 3 miles from home, i found a good spot & jumped in to try unbolt it...i could feel the bolts but but struggled to get the allen key in the hole upto my neck at full arms stretch. after 10minutes i was too cold and had to give up. In the end i drove back with it banging. Im going to look for a different style of cutter that is less complicated. After this experience im not sticking with the same.

 

[Tranona]

The fixed cutter does not come out by accident. They are normally very reliable if set up properly according to the instructions. The cutter should be mounted on the shaft so that the tongue on the fixed cutter is roughly halfway in the V shaped wedge. This allows the shaft to move fore and aft as you go in and out of gear. It seems that it has come out is probably probably due to being set to far aft and when you have engaged reverse the engine/shaft has moved back on its mounts enough for the tongue to pop out.

Scissors type cutters are way superior to the simple disc type and worth making the effort to set it up properly.