Clutch plates??????
Hello Ted, Thanks for the question. I’m not 100% sure because there could be a few items going on. I believe that the HBW50 is rated to max HP of 25. If the current system has been in service for a great deal of time you may be simply seeing the clutch plates worn due to the amount of HP the W21 is producing. One could reason that the HBW50 could be taxed by the W21. The reason you can shift it by hand when the engine is off, could be that you have eliminated the pressure and heat that may have developed while the transmission was in gear rotating the prop. Your cable may also cause a ton of problems. Rust and corrosion is a big problem but once a cable fails its not likely to work moments later without a great deal of working. Your transmission oil may be low? Low trans oil is will make shifting very hard and could increase in effort as time goes on due to a decreasing level of fluid. Is the fluid black? Black fluid represents burning or slipping. Sorry, But my guess is that you may have to have a person contort themselves and take a look. Good luck and hopefully there is something above that may shed light. Kevin (Plates or oil level are my guess)
