Engine RPM under load

[formariz 11,987]

So on my mowing tractor with a k241 and using a 48” deck , the engine drops about 700 RPM when deck is activated. Goes from 3500 at full throttle to about 2800 with deck. 
 Would it be advisable to increase engine speed to 3500 with deck on? I know that I would have to be careful not to rev it full throttle with no deck load. I am thinking that the extra RPM would make for a better cut with more lift on blades. 

[8ntruck 6,998]

Full rpm will make the deck cut better. 

 

Have you checked for issues in the deck and mule drive that might be causing drag?

 

I've got a 42" RD deck that started to pull the engine rpm down last fall.  Got to get it up on saw hordes to see what is going on with it.

[lynnmor 7,305]

Apparently your governor isn't adjusted properly, the RPM should not drop very much under load.  Check your engine manual for setting up the governor.

[Tuneup 1,433]

or maybe a K241 is a bit small for that load? My 301 had difficulty before the rebuild - moved that deck to the Onan for the torque.

[Ed Kennell 38,132]

Is the throttle plate wide open when it drops to 2800?    If it is, no gov adj will increase the RPM.

[squonk 41,067]

I would do as ED Dog said as well as 8ntruck said Cas. I'm betting on the mule and or deck pullies. Take the deck right off. Check the mule pullies and take off the deck belt and check all the spindles and idler. Make sure the idler slides good too.

[ri702bill 8,316]

I see the same on the 854 8 speed with the 36" geardrive deck. I bump the WOT RPM with the deck engaged to about 3250 - no more. I'm the guy that has to replace an over-reved engine......

I adjust ground speed to keep the RPM's up...

[formariz 11,987]

All pulleys on deck and mule drive are new along with pretty new spindles. I have to look over the engine’s throttle assembly and governor a little better. Problem may be there. I just don’t know if this much drag is normal since I have nothing to reference to. Yes engine may be a bit underpowered for this deck. 

[squonk 41,067]

Maybe even the 10 is just tired. A little low on compression like valves not seating well. You can be down on power and not have any tell tale smoke. Also worn points effecting timing. 

Edited June 4 by squonk

[kpinnc 12,004]

3 hours ago, lynnmor said:

Apparently your governor isn't adjusted properly, the RPM should not drop very much under load.  Check your engine manual for setting up the governor.

 

48 inch deck is absolutely the upper limit for 10hp. 

 

But to answer the question, I would not rev the engine to reach 3600 under load. If your engine can't maintain or at least recover to 3600 after a heavy spot of grass, it's not healthy enough to carry said load to begin with. 

[Fordiesel69 263]

I am thinking everyone may have missed the boat here.  Lets reset our thinking......

 

1.)  Open hood so the throttle linkage is visible.  

2.)  Turn the deck on and off, and you should see the throttle linkage and gov arm move quite a bit as the engine attempts to recover the deck load.  Conversly when the deck is turned off and the load is dropped the gov will close the throttle very quickly to prevent over rev.

3.)  If this is not happening and the linkage is NOT moving,  do not run the engine any longer.  Gov gears have been known to break apart and fall down into the engine.  When this happens, the connnecting rod dipper will almost always break off, and in short order will destroy the engine.  Dont assume this has happened, just keep this in mind.  Post back and we can help you carry out a static gov adjustment.  It is kind of hard and I do not want you to start with that yet, as if done incorrectly will create a whole new problem for you.  

4.)  If the throttle linkages are moving which I assume they are, and the engine is attempting to change speed but physically cannot recover, there is only one way to diagnose.  Is it the engine or the load that is the problem?  How do you find out?

5.)  If you have a manual, drive it with the hood open in 3rd gear and use the brake pretty hard.  Is the gov linkages moving and is the engine recovering?  If yes you have a problem with the deck.  If no, then the engine is weak due to wear, carburetor adjustment, or valve issues.

6.)  If you have a hydro, climb a steep hill with it and watch to see if the engine can recover.  

 

Post back what happens.  No sense chasing all kinds of things.  Is it the engine or the deck causing your issue?