Short answer- I know, lower cable. It intermitantly wont engage reverse and the shift interupt switch is working properly but thats not the problem. when it does this it will grind but wont engage other times it works just fine, when it wont engage ive removed the cable from the interupt switch and manually operated it but it still wont engage- bigger problem?? the only other thing I can think of is there might be a lot of crap built up in the cavity at the other end of the cable -the boat is moored and was last year too. If this is the case (i hope) what could i treat that with? Im guessing albatment paint wont work because there isnt any real water movement in there??