BX24 Engine RPM when using MMM

[thavil]

I am a brand new owner (30 hrs in 3 weeks) of a 2008 BX24. This is the first tractor I've owned, so I am trying to learn everything as fast as possible. What is the recommended engine RPM when using the MMM. I have a 60" MMM and mow 5 acres of horse pastures. Right now, the grass/weeds are approximately 6" tall. My salesman told me to always mow with full engine speed but when I read my manual, it said to never run at full engine speed for the first 50 hours. I listened to him before I read the manual for my time out, so I have about 2 hours of running time at full speed. Needless to say, I didn't get the best fuel consumption either.

Full RPM on my BX24 is around 3300 RPM and I have been mowing at around 2800 RPM. Any thoughts on the best RPM to mow at? Thanks.

 

[sixdogs]

You should break in your engine with a variety of speeds for the first hours. I wouldn't worry about it as the tractor will likely outlive you and the kids/grandkids anyway.
In thicker grass I run towards the higher end of the PTO@ 550 RPM speed and at lower grass maybe 25% less. I see no need to run at full RPM with regular height grass. Works for me but answer is very subjective so it's open to debate.

 

[thavil]

Thanks sixdogs. After I typed the post, I realized what a subjective question it was. I guess I just wanted to make sure that it wasn't common knowledge to run the MMM at full RPM.

 

[slewisma]

Mow at the RPM that gets the job done. If the weeds or grass are high, use a higher speed to spread the clippings better. Otherwise, mid-speed will save fuel. One other rule: high RPM on hills. The HST will work MUCH better with more RPMs in terms of holding position on the hill.

I mow at about 2,500 RPM with the 54" finecut MMM and bump it up closer to 3,000 on the steep parts.

 

[Renob]

I usually engage the mower at approx. 1800 rpms then increase to the Kubota recommended operating rpm of approx. 3100 rpm for the MMM. Great cut and thats where Kubota says to run it.

 

[dannydan3]

Mow at the RPM that gets the job done. If the weeds or grass are high, use a higher speed to spread the clippings better. Otherwise, mid-speed will save fuel. One other rule: high RPM on hills. The HST will work MUCH better with more RPMs in terms of holding position on the hill.

I mow at about 2,500 RPM with the 54" finecut MMM and bump it up closer to 3,000 on the steep parts.

After the nasty experience of buying a new one, I am not taking any chances with the lower RPM's and the lower fluid pressure to the HST.

 

[thavil]

Thanks everyone for the great input. I will put your experience to good use. Renob reminded me of something I tend to forget. I sometimes forget to lower the RPM's before I engage the MMM.

 

[slewisma]

After the nasty experience of buying a new one, I am not taking any chances with the lower RPM's and the lower fluid pressure to the HST.

That's exactly why I crank up the RPM's for anything steep or thick but I may take your advice and run it higher all the time. I don't want to replace HST anytime soon.

 

[Mustangous]

In thicker grass I run towards the higher end of the PTO@ 550 RPM speed and at lower grass maybe 25% less.

How do you know what rpm the pto is at?

After the nasty experience of buying a new one, I am not taking any chances with the lower RPM's and the lower fluid pressure to the HST.

What do you mean? Could you elaberate? Sorry if i missed something?

 

[actionaj]

I mow at about 2950 RPM with my RCK54 it seems to give the best cut. I ingage and disingage the blades at 1500 to 1600 RPMs.

 

[KeithInSpace]

I ALWAYS engage at idle...no reason to do any more than that. This imparts the least amount of stress on all components involved and doesn't do anything but burp a small amount of soot out the tailpipe...I mean front-pipe...mouth-pipe? What'cha call it...exhaust pipe.

I used to mow just off WOT, but the bagger didn't suck up too well, so now I run at WOT all the time. Hasn't been that big of a deal. If I didn't have a bagger, I'd probably run as others have stated they run...

 

[Schultz]

After the first season I put gator blades on my 60" BX2200 mower. That made all the difference, they have a lot more vacuum, mulch a lot better and stay sharper longer. It pulls the grass up that the front tires flatten at fairly low RPM's. When I mow, I usually vary the RPM to the conditions. I can't mow at full ground speed and stay on the seat, so I usually lower the RPM for sparse summer time grass and full in the spring and fall for mulching the thick grass or leaves. On the other hand my wife mows wide open all the time, and she does most of the mowing of our 3 acre lawn.
I've been meaning to sell my original blades, anyone want them?

 

[BotaBigot]

The engine is rated to run all day long at max RPM. Having said that, I think a lot of us are used to diesels running at a lower RPM than the BX...which may have something to do with the different recommendations. I don't often run mine full speed. I use the lowest RPM that gets the job done. For my mowing conditions, that's about 3000 RPM. Like KeithInSpace, I kick it up with the bagger...expecially if leaves are damp/deep...

 

[thavil]

Thanks for all of the suggestions. Everyone has made good points in their recommendations. My main dilemma was whether to listen to my salesman (mow at WOT) or what the book said for the first 50 hours break-in period. I also learned something valuable about engaging the PTO at low RPM's. Being new to the tractor world, I wasn't sure about running at max RPM's for an extended period of time.

 

[KeithInSpace]

Easy. Do something other than mowing to 50 hours. Simple 'nuff

Honestly, I think I just mowed off WOT for a while.

 

[ampsucker]

i mow our "lawn" at about 2600 with sharp blades. kick it up if very thick. i actually bogged down the engine for the first time in some very thick stuff. i was experimenting just what the tractor could do so ran it at about 3.5 inches through some extremely thick wet grass and it started balling up at the chute and building up under the deck to the point the engine almost died. that was around 3000 rpm.

i did try not to work it under heavy load until past 50 hours. i did some WOT driving down the road just to get full travel on all the engine components but did not work it at that speed for extended periods. would recommend not mowing at WOT until after first 50 hour service is done.

i also notice my temp gauge creeps up about halfway between the mid point and hot when mowing above 2800 or so in hot weather. this is with a clean intake screen. other posters seem to think this is due to the placement of the temp probe in the engine and is not cause for concern. well, i don't like it, but am not sure if there's anything to be done about.

i also find i get a better cut in thicker grass when mowing in "turtle" gear and only go at "rabbit" speeds when the grass is already pretty short.

planning to try the highly recommended gator blades next year.

amp

 

[rdsaustintx]

i also notice my temp gauge creeps up about halfway between the mid point and hot when mowing above 2800 or so in hot weather. this is with a clean intake screen. other posters seem to think this is due to the placement of the temp probe in the engine

yet other posters figure it's because the tractor is working its little azzoff.

seriously, you don't gotta baby your new baby much. get out there and play. have a blast. worst thing you can do is not run it. it LOVES going WOT, you'll see.

RDnT

 

[thavil]

KeithInSpace, I wish I could do other things besides mowing for the first 50 hours but to be honest, I like operating this thing so much, I have mowed both of my pastures twice in the month I've had it. I now have 35 hours in 4 weeks. I mow at 3 3/4 to cut the tall weeds but leave enough for the horses. We've had enough rain this year that the pastures are still growing. I've used a Craftsman 48" GT5000 for 4 years of cutting, so the BX24 is just too fun to stop.

After I started the thread, someone pointed out that the question was very subjective. I now see that there are so many different ideas out there, from all of the seasoned guys and gals, that the best thing to do is use some common sense with everyone's suggestions and read the manual before starting.