Hi, I have a 361 with a Westerbeke 30B3 (27HP) and a 15 in. 3 blade fix propeller. Over the past years the engine tachometer was erratic and I don't think it was indicating the correct RPM. This spring I bought a laser tachometer and calibrated the Westerbeke tachometer and cleaned up the connections. It now reads the correct value and I have adjusted the idle RPM to 1175RPM exactly like calibrated and tested by Westerbeke for this engine. When I am at the dock and in neutral, I can run the engine up to 3750RPM which is the value reported by Westerbeke. This spring I have changed my propeller for a 16 in. 3 blades Variprofile VP64 with 11 forward pitch and 9 for reverse pitch (Suggestion by Variprofile for the 361).
With the new prop I can only get to a maximum of 3200RPM and a max speed around 6.4kn, I used to get 7kn pretty easily. I should have made a table of speed vs RPM with my fix prop but I did not do it because of the tachometer problem. Could you please let me know what speed and RPM combinations you can achieve with a 30B3 in a 361 with 3 blades. This would help me adjust my new prop, the pitch is probably wrong. Although the idle RPM is fine as soon as I put the shifter forward or reverse the engine rpm drops to 1000 sometimes less and the engine start to shake.
Your input will be greatly appreciated. Thanks in advance for the help
Georges
With the new prop I can only get to a maximum of 3200RPM and a max speed around 6.4kn, I used to get 7kn pretty easily. I should have made a table of speed vs RPM with my fix prop but I did not do it because of the tachometer problem. Could you please let me know what speed and RPM combinations you can achieve with a 30B3 in a 361 with 3 blades. This would help me adjust my new prop, the pitch is probably wrong. Although the idle RPM is fine as soon as I put the shifter forward or reverse the engine rpm drops to 1000 sometimes less and the engine start to shake.
Your input will be greatly appreciated. Thanks in advance for the help
Georges