Volvo Specs

[Wayne Fredrick]

Don't know if you can answer this question on a Volvo diesel or not, but here goes. I have a 78 HP TMD22 Volvo turbo diesel on my Hunter 450. Some of the earlier boats came with Volvo's before they switched to Yanmar's. The engine is great, very quiet, the impeller is a breeze to replace compared to the Yanmar, but in reading the Owner's Manual, it calls for the correct operating range for this engine to be 4500 rpms. A guy on my dock has larger Volvo's on his power boat and says it is better to run the turbo diesel at higher rpm's for efficiency. I cruise at 7.5 knots at 3200 rpms. Have called Volvo trying to get an answer if this engine should be run up that high or not, no one seems to know. Any input would be appreciated.

 

[Bob Beck]

450's with Volvo's

I too have the same Volvo and I run it at about 3600. I have been told that it is better to run them at 75% or better. I have had no trouble and when necessary run it higher, if the situation calls for more rpm's. The Volvo people are NO HELP, they always refer you to a local guy who doesn't even know what the model is. I have even gone to their VP of US operations and he just sits there and gives zero answers too! Ask them how to shut the engine down other than by turning the fuel off(if there was a malfunction at the ignition switch), that will get you a DAH answere too!

 

[Gordon Torresen]

Volvo TMD22 RPM

Your TMD22 is rated for a maximum HP of 78 at 4500 RPM. This usually means that that is where the governor is set and that you can run short bursts at that speed. If you have the correct prop, you should start to lug down at about 4050 RPM when in gear. A comfortable long term running speed would be 3600 or less. With all the torque that the engine produces you could probably turn any RPM that you choose. You should determine the proper RPM by plotting an RPM vs hull speed graph. This will show the most efficient speed to run with the conditions on your boat. It can tell you if you have the optimum prop, when to clean the bottom, if you got a bad batch of fuel, etc.