Red Mark on the Tachometer

   / Red Mark on the Tachometer #1  

boomer613

Silver Member
Joined
Apr 25, 2012
Messages
126
Location
Northern part of AL
Tractor
Kioti DK40SE /W FEL
As a general rule, should you run the RPM to the red mark on the tachometer when using the PTO for implements? Do you guys use difference RPM for different implements such as a tiller vs. a rotary cutter. Bush hogging in high grass vs. short grass vs. saplings. Thanks.
 
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   / Red Mark on the Tachometer #2  
The tach red triangle is to mark the peak HP/torque for the tractor's PTO use. It does NOT mean one has to run all implements at that RPM. Some implements like a winch may need the max RPMs in some use and not so high an RPM in other uses. Same with most PTO driven implements. Some require maximum torque and some don't. Some will require it all the time and others won't. Good judgement is needed in any given circumstance to determine the best use of the tractor, operator, and implement- keeping operator safety in mind.
 
   / Red Mark on the Tachometer #3  
I thought the red mark on the tach marked the rated RPM for the PTO. ie. that is where the 540 RPM pto is running 540 RPM.
 
   / Red Mark on the Tachometer #4  
The owners manual doesn't address it. I think it's the max rpms before the rev limiter kicks in. Anytime I have exceeded it(like going down a hill) the engine cuts out until rpms fall below the line.
 
   / Red Mark on the Tachometer #5  
It is the 540 PTO rpm according to the fellow that delivered my DK. As has been noted in some of the other threads DO NOT start your implement with it already at the mark. I start my Bush Hog at the lowest speed I can and then gradually bring it up or close to the mark. You don't need it to be right on it and can run it slower if you wish. My SQ172 seems to operate best about 1 tick lower than the 540 mark.
 
   / Red Mark on the Tachometer #6  
The tach red triangle is to mark the peak HP/torque for the tractor's PTO use.

Coyote is correct here. It is also the point where the PTO is at 540. The design engineers take the point where torque & HP are at their best combined values then based on that RPM gear the PTO accordingly to optain 540.
 
 
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