Maximum engine RPM

[Madhatter]

Anyone know what the maximum engine rpm should be on my L3450?

I noticed today that it maxes out at about 2500rpm or about 100 rpm higher than the line for the 540 PTO speed on the tach. The tach reads up to about 3500.

 

[cerlawson]

This reminds me of the story of the speeding driver. When the cop asked him why he was speeding, he replied that the needle had not reached the high number yet on his speedometer.

 

[North Idaho Wolfman]

2500RPM's is about right.
I never really have a need to run mine up that high.
Why are you wanting to run it up there?

 

[Dave_eng]

You have to appreciate the torque curve of the engine. The recommended rpm for 540 pto speed will be past the peak of the engine torque curve. In this way, as the pto sees a heavy load and starts to slow down the engine torque will be increasing and thus taking up the increased load and maintaining a relatively stable engine speed.
The rpm's you comment on seem to follow the strategy I explained above.
Dave M7040

 

[Madhatter]

Why are you wanting to run it up there?

No real need to run it that high. The max RPMs just seemed a little on the low side to me, but then again this is my first diesel. In the little bit that I have mowed with it, both with the belly mower and the brush-hog, it seemed to like to be around 2000rpm give or take.

 

[North Idaho Wolfman]

Yes diesels run at a lower RPM compared to gas engines, but as Dave stated they create maximum torque at a much lower RPM.

Try running the PTO is the 1000RPM range and drop the engine RPM in half so like 1500RPM, mine purrs like a kitten when I do that.