Increased power in my L2501

[Joel K]

First post here. I've been reading this forum for quite a while now and finally just registered.
I'm not a new tractor owner just new to kubota in the last 3 years. I've owned and operated just about every type of earth moving equipment and landscape equipment. Prior golf course builder/superintendent. Anyway, the reason for my post is related to the L2501 and the hidden power it may have. What I've done with mine is adjust the throttle linkage stop and I am now able to achieve 3000 rpm. The only time I need to increase rpm above 2300 is when I'm driving out of a hole with a full bucket of dirt. I have no idea what the hp increase is or if it even improved torque at all. I do know however i can push the tractor a little more without stalling it out.

Has anyone else done this and checked it on a dyno? And no I'm not worried about voiding the warranty.

Also before the comment comes up. I don't use a skid steer or larger tractor due to limited access to yards and the Kubota doesn't tear up lawns too bad. I use it to install mostly above ground pools. So basically sod removal,ground leveling, some deep end digs and a few in-ground pools. For in-ground pools I have the hole dug and move all the dirt with the Kubota. I have a piranha tooth bar, custom width bucket at 57" QA. I've also increased the hydraulic pressure 500 psi at the bypass valve with no issues at all. Tires are loaded and on the back is a bb1260. I also have QA forks.

The L2501 is a great tractor and I work it hard. My last was a B2650 however it just wasn't heavy enough for all the ground engagement I did with it.

Happy Thanksgiving

 

[jtboney1]

Thanks Joel for the info. I, too, have a L2501 and am slowly learning what it can and can't do. It's the smallest tractor I've ever owned but so far the can's outnumber the can'ts.

The only time I feel that I need some more hp is when I'm bush hogging in pretty heavy stuff. The 5' cutter pulls my engine down considerably and I have to go pretty slow. Since I've got plenty of time to get er done I probably won't ever turn the rpm's up to boost it's power.

I would like to increase the hydraulic pressure at least up to the maximum. When I take mine in for service I'm gonna ask my dealer to check and adjust the pressure. If I don't get the results I want I am going to buy a gauge and fittings and do it myself. There is an excellent thread on here somewhere about adding shims to the pressure relief spring.

 

[armylifer]

I read somewhere that the D722 engine in my tractor was also used in other equipment like generators and such, and that the max RPM was set higher in those other applications than it is for the tractor application. I don't remember where I saw that but I bumped the RPM in my tractor engine from 3200 max RPM to 3500 max RPM. If I remember the article correctly the 300 RPM bump in my engine raised the HP from 18 HP to near 20 HP. I posted a link to a spec sheet for the D722 engine.

One other thing I did at that time was raise my idle RPM from 1200 to 1500. I use a sprayer for our trees very often in the summer and I was always having to bump the RPM up to 1500 when I used the sprayer so I just figured that I would bump the idle RPM to the point where I used it the most and left it there.

https://www.dieselenginemotor.com/kubota/supermini/D722

 

[SRG]

Interesting. According to tractordata.com, the L2501 is rated at 2200rpm. I don't know if that's 2200rpm to achieve 540rpm at the PTO, or if that is where max HP is rated?

I'd love to get 3-400 more rpm out of my 870. When it's at max throttle (2600rpm), it feels like it has alot more potential. I'm gonna have to look into this now.

 

[SDT]

Interesting. According to tractordata.com, the L2501 is rated at 2200rpm. I don't know if that's 2200rpm to achieve 540rpm at the PTO, or if that is where max HP is rated?

I'd love to get 3-400 more rpm out of my 870. When it's at max throttle (2600rpm), it feels like it has alot more potential. I'm gonna have to look into this now.

Not familiar with the specs of the 2501, but do know that tractordata is not to be trusted.

SDT

 

[olsarge]

How do you adjust the stop?

 

[armylifer]

On my engine there are 3 adjustment screws on the throttle body. 1 is for the fuel cutoff solonoid, 1 is for the idle adjustment and 1 is for the high speed adjustment. The idle speed adjustment screw was easy to see and adjust. The high speed adjustment is under the idle speed adjustment screw. Both the idle adjustment screw and the high speed adjustment screw has a wire going through the screw heads. I cut the wires off the screw heads, loosened the lock nuts on each screw and made the appropriate adjustments then tightened the lock nut on both the screws. If I remember correctly, to raise the idle speed I had to turn the screw clockwise. In order to raise the max RPM I had to turn that screw counter clockwise. I hope this helps.

 

[thepumpguysc]

Joe is correct>> "IN" to raise the low idle rpms.. "OUT" to raise the hi idle rpms..
Now if u want more fuel?? Theres a screw for that to.. just google it.

 

[Dunbar]

Subscribed

 

[Joel K]

I cut the wire for the main linkage stop. Back out the stop screw until you achieve your target rpm. I didn't touch the other adjustments.

Sent from my Pixel 2 using Tapatalk

 

[olsarge]

I think that's above my pay level! I'd screw it up.

 

[tractor junky]

I too have a 2501. my concern with more rpm is this; what happens when you guys are using the pto? Are you changing the 540 range on the dash with increases? seems like you might be. I'd like more power for brushing hogging but still want to maintain proper pto speeds.

Tractor junky

 

[armylifer]

The higher the rpm goes the faster the pto spins.

 

[North Idaho Wolfman]

I too have a 2501. my concern with more rpm is this; what happens when you guys are using the pto? Are you changing the 540 range on the dash with increases? seems like you might be. I'd like more power for brushing hogging but still want to maintain proper pto speeds.

Tractor junky

You can't have both!
We've went round and round with this, Increasing the RPM does NOT increase the HP, it just increases the speed at which the motor is spinning, you would have to slow it down to keep the PTO RPM's in the safe range.

If you need more HP get a bigger tractor!

 

[leoric]

You can't have both!
We've went round and round with this, Increasing the RPM does NOT increase the HP, it just increases the speed at which the motor is spinning, you would have to slow it down to keep the PTO RPM's in the safe range.

If you need more HP get a bigger tractor!

A certain really long thread ending in a dumpster fire comes to mind.

 

[Shadetree03]

Since HP = Torque X RPM/ 5252 ; raising RPM theoretically increases HP if torque is constant...

on the Kubota 1703 triple engine, the top of the torque curve is around 60 which occurs around 1600 rpm and falls off slightly above and below that.

A beautiful part of that is when brush hogging at 2100 rpm if heavy cover pulls it down a little, the increased torque helps pull back to the 24-25 HP range...

Probably could get 28 HP out of it at 2600 rpm or so, but fuel economy, wear etc would suffer. I think I'll work on my fuel delivery issues, and enjoy the little torquer as is...

My gas Rotax 1330 engine also a torquer pulls 75 lbft of torque at around 3000 rpm, but will wind to 7500 rpm deliver 100 HP plus... but I wouldnt brush hog with it..

 

[North Idaho Wolfman]

A certain really long thread ending in a dumpster fire comes to mind.

Dumpster fire.... more like, out of control chemical warehouse fire!

 

[motorhead]

For what it is worth, I would NOT cut any seals off of the High idle (High engine speed stop) if you are still under any warranty. Once you do this, cut the seal wire, you become your own warranty station.

 

[lugbolt]

raising RPM theoretically increases HP if torque is constant...

Big "IF". IF torque remains constant, which it doesn't-not on that engine, without fuel.

Problem with turning up the speed is that now the transmission turns faster, the pto turns faster as well. Fan and alternator spin faster. Hydraulic pump spins faster and moves more oil. Was it designed for it? Dunno. I ain't no engineer.

Then if someone is on it (owner, employee, etc) and hurts themselves, if it's known that the thing has been modified, Kubota is going to step away from it...and then most of the liability has a good chance of falling on guess who?

Got a call earlier. Friend is in the hospital, 3ph mounted backhoe "came off" (that's all I know) while in operation, crushed his leg. Leg may not be saveable. This was a city-owned tractor. He is, or was, 58 days from retirement.

 

[motorhead]

Got a call earlier. Friend is in the hospital, 3ph mounted backhoe "came off" (that's all I know) while in operation, crushed his leg. Leg may not be saveable. This was a city-owned tractor. He is, or was, 58 days from retirement.

Wow, Hope he pulls through this! Please keep us posted.
We had a Pastor of a church a few towns away from me who had retired just a week from his church of 25 plus years. He was walking and a young girl, DRUNK driving, hit him and killed him.