4200 HST Losing Power

[wnooitge]

Hi All,

I've been lurking for a few years now and have learned a lot but now I need your help.

I have a 4200 w/970 hours. I'm experiencing power loss of around 800 RPM after using it for 30 - 40 minutes. When it losses power there's no smoke just the loss of horsepower.

One scenario is that I'm mowing for 40 minutes when the tractor loses power. I stop it, stop the mower and it gains the RPM back. I then start moving forward and the RPM drops again. I park it for 15 minutes and I can run it for another 20 minutes before it losses power again.

I changed the fuel filter, primary air filter, and performed an oil change. I made sure that there is good air movement in and out, that the coolant level is correct, and that the transmission oil level is okay. Also, the needle on the temperature gauge is consistently a third of the way up.

The only other thing that I do have is a leaky female coupler.

Has anyone come across this? Any ideas?

Thanks in advance!!!

 

[kennyd]

Welcome to TBN

You have a strange problem there for sure

My two thoughts are:

Overheating: I know you said the temp gauge doesn't show it, but they are notoriously inaccurate, Not just JD's per say-but all OEM's, including automobiles. Do you have another way to check temperature? I have one of those infrared handheld point-and-shoot ones that works great...

Injector pump: Mounted on your engine to control fuel flow to the injectors and set timing. They can get heat sensitive also as they age and tolerances change, but at your hours it should be OK. It's definitely not a DIY repair though...

Are you sure the radiator is clean, and the fan belt is tight?

 

[Mech]

Hi All,

I've been lurking for a few years now and have learned a lot but now I need your help.

I have a 4200 w/970 hours. I'm experiencing power loss of around 800 RPM after using it for 30 - 40 minutes. When it losses power there's no smoke just the loss of horsepower.

One scenario is that I'm mowing for 40 minutes when the tractor loses power. I stop it, stop the mower and it gains the RPM back. I then start moving forward and the RPM drops again. I park it for 15 minutes and I can run it for another 20 minutes before it losses power again.

I changed the fuel filter, primary air filter, and performed an oil change. I made sure that there is good air movement in and out, that the coolant level is correct, and that the transmission oil level is okay. Also, the needle on the temperature gauge is consistently a third of the way up.

The only other thing that I do have is a leaky female coupler.

Has anyone come across this? Any ideas?

Thanks in advance!!!

When it loses HP have you tried to pull off or loosen the fuel cap. Maybe it isn't venting correctly.

 

[Egon]

I'd suggest a heating problem. Do you use for other than mowing and does it act the same?

 

[kennyd]

When it loses HP have you tried to pull off or loosen the fuel cap. Maybe it isn't venting correctly.

Great Idea

 

[wnooitge]

You guys are great!!!

kennyd, I don't have another way of checking the temperature. The radiator is clean. How much play is acceptable for the fan belt?

Mech, I haven't tried that. I'll try it and let you know.

Egon, I was mowing it seems 24 hours a day until this happened so odds have it that it would happen when the blades were turning. I have tried running it around the field after it's been resting for awhile and it does drop the RPMs.

 

[Egon]

Is the inside of the radiator clean?

 

[wnooitge]

egon, I actually haven't touched it since I got it. Looks like I'll be flushing the cooling system this weekend. I'll let you know if that does the trick.

Thanks again for the reply.

 

[wnooitge]

Hello Everyone,

Well, I flushed the radiator which it desperately needed. But it didn't cure the problem. Took it out for a mow tonight and the RPMs dropped after 20 minutes like before. I even took the fuel cap off which was suggested but I still came up with the same results.

Noticed one thing though. When it lost RPMs I stopped the mower and brought the tractor to a stop the RPMs picked back up as usual. But then I worked some of the hydraulics like raising and lowering the deck and moving the FEL controls, the RPMs would fall right off, meaning it would lose about 1000RPM. Not sure if it has to do with anything but thought I'd mention it.

Just a couple of ideas. Could the leak in the coupler have anything to do with this? I've changed every liquid in the tractor except for the transmission/hydraulic fluid. Could that have anything to do with it?

Or is there something you can think of that I should be checking?

Thanks again for everyone's help.

 

[Egon]

Some how I suspect it is a heat problem?

How did you flush the rad and what type of coolant did it have in it?

 

[wnooitge]

Hi Egon,

I emptied the radiator fully. I added water to a cool engine and added a bottle of radiator flush. I ran the tractor for about 20 minutes and drained the radiator fully. A lot of crud came out so I waited till the engine cooled and ran some water through it until the water was clear. I then filled the radiator with Prestone pre-dilutted 50/50. Does that sound right? Just to throw something out, could the thermostat be failing?

Thanks for replying so quickly.

 

[kennyd]

Here is a thought:
Your mower is raised and lowered via a Rear Remote (3rd SCV) correct? The cable that goes from the lever down to the valve is known for sticking. I am thinking your lever is not returning to neutral, and the valve is staying open causing your hydraulics to overheat very quickly by going into relief mode.

Does the lever operate smoothly?

 

[wnooitge]

kennyd, The lever seems to be operating smoothly. Is there something that I should be greasing where the cable attaches to the valve? Could the leaky coupler cause the hydraulics to go into relief mode?

 

[kennyd]

A leaky coupler will NOT cause ant of your problems! Unfortunately, it's not a lack of grease issue. It's just the cable inside the sheath that's gets tight. Just make sure the lever is centered.

 

[wnooitge]

kennyd, Thanks for the suggestion. Next time I go out I'll make sure the lever is centered.

 

[wnooitge]

Egon, this is a re-post so that my reply to you didn't get lost in the thread.

I emptied the radiator fully. I added water to a cool engine and added a bottle of radiator flush. I ran the tractor for about 20 minutes and drained the radiator fully. A lot of crud came out so I waited till the engine cooled and ran some water through it until the water was clear. I then filled the radiator with Prestone pre-dilutted 50/50. Does that sound right? Just to throw something out, could the thermostat be failing?

Thanks for replying so quickly.

Well I'm off to push mow 5 acres.

 

[gary_dsc]

Been there, done that. I wish I were closer to you. I'd be happy to help you out. Sounds like it might be time to get the dealer involved.

 

[wnooitge]

I'm changing the thermostat tonight, I'll let you know if it cures my ills.

 

[Boris1]

Hello,

I had a similar problem and it was caused by debris in the fuel tank. The rust particle would gravitate to the fuel intake after 15-20 mins of operation restricting the flow and run fine after sitting for awhile? Just a thought.Hope it helps?

Matt

 

[wnooitge]

Boris1,

What did you do to fix the problem?