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?