I just bought a 2005 RT40 with a chain trencher. I used it for about 4 hours and now the chain spins in reverse all the time. I can't shut the trencher off at all and have no idea where to start.
Welcome to HEF cbruce73401. :drinkup The control valve for trencher chain should be on the left fender, #3 in illustration below, that's where I'd start.
hi cbruce, I also planned to buy a used RT40 for micro trenching work. Wondering the engine horse power is good enough to do the trenching work at normal asphalt and concrete urban area to trench to the depth of 300mm.