Farm Pro 2420 Problem

[R Barger]

I just bought a 2420 and when you first start it it runs at around 500 rpms and won't rev beyond that for 3 to 4 minutes. Then it will take fuel and throttle up like it is should. As long as it is warm it will run well till it cools completely and then it will do the same 3 to 4 minute thing again. Anybody have any Ideas?

 

[Bob Rooks]

Sounds like the governor might need some oil.

 

[R Barger]

Sounds like the governor might need some oil.

When I got the tractor I had the same thought so I drained the oil and it had way too much oil in it. The oil looked clean,just way too much. I put back 4 ounces as the jinma manual says but it didn't change it.

 

[Bob Rooks]

What year is it? Now it sounds like an EGR issue since it seems temperature related, relating to EPA emission requirements. Barring that, it could be a sticking rack/barrel-plunger assembly.

 

[Ricks284]

I had a similar problem with my Jinma recently, but it doesn't sound identical... so I'll just throw this idea out there for you to consider. Mine was starved for fuel and the engine rpm was erratic. Sometimes it would run fine, and other times it would almost stall. The shut-off valve under the diesel tank has a rubber piece inside that disintegrates over time. Mine was almost completely blocking the flow, so I fixed it by cutting out most of the rubber piece. It works fine now and I don't really care that the shut-off valve no longer works.

Your problem is probably unrelated, but I thought it might be worth checking. It's pretty easy to check if you're getting full flow through that valve -- just disconnect the fuel line before the filter and empty it into a jar.

 

[R Barger]

I am beginning to think injector or injector line leaking off when I let it sit. Today I started it and cracked the injector line on the front cylinder and at first there was no fuel , then suddenly there was fuel so I closed the line and it ran normal.

 

[R Barger]

I had a similar problem with my Jinma recently, but it doesn't sound identical... so I'll just throw this idea out there for you to consider. Mine was starved for fuel and the engine rpm was erratic. Sometimes it would run fine, and other times it would almost stall. The shut-off valve under the diesel tank has a rubber piece inside that disintegrates over time. Mine was almost completely blocking the flow, so I fixed it by cutting out most of the rubber piece. It works fine now and I don't really care that the shut-off valve no longer works.

Your problem is probably unrelated, but I thought it might be worth checking. It's pretty easy to check if you're getting full flow through that valve -- just disconnect the fuel line before the filter and empty it into a jar.

Tomorrow I will check fuel flow to the pump.

 

[Ricks284]

I am beginning to think injector or injector line leaking off when I let it sit. Today I started it and cracked the injector line on the front cylinder and at first there was no fuel , then suddenly there was fuel so I closed the line and it ran normal.

Okay, well maybe you just had air in the system. Air is exactly what I suspected at first, before finding the clogged shut-off valve. If yours continues to be erratic, you might still check the gravity fuel flow from the tank, just to be sure. Good luck!

 

[R Barger]

I checked both fuel lines going to the pump today(no fuel). I have never seen a setup like this I'm not sure if the lines are run correct. Someone has put a new pump on it. The line from the strainer bowl is attached to the pump where the primer is. I'm totally confused at this point.

 

[Bob Rooks]

The plumbing is correct. Flow is from the tank (sediment bowl) to the lift pump, to the secondary fuel filter, to the injection pump, and then return line to the tank (they all do it that way). Some models will have the return line going back to the lift pump suction, but that is a dubious practice. Check to see if you have an in-tank screen. If you do, remove it, they are notorious for plugging up, especially if you have a dose of diesel bugs (looks like brown/black sludge). You also have a small screen inside the lift pump suction banjo bolt (if it hasn't been removed), another source of plugging.
The barrel/plunger assemblies and the injectors will not hold the 2,200 psig popping pressure for long (1 hour at best), but they make it up with every turn of the engine.

 

[Bob Rooks]

This pic shows the fuel flow path, the exception being the return to the lift pump. Your return goes back to the tank, either directly or via the injector leak-off lines.

 

[R Barger]

This pic shows the fuel flow path, the exception being the return to the lift pump. Your return goes back to the tank, either directly or via the injector leak-off lines.

View attachment 467205

If I take the line loose where it connects to the primer pump I should have a gravity flow of fuel? I removed the line on the exit side of the primer pump and had no fuel flow.

 

[Ricks284]

You're right - should be gravity flow there. You can try turning the shut-off valve to see if you might get lucky with an easy fix. But you'll most likely have to pull the plastic bowl/valve assembly off the bottom of the tank. Then you can check the in-tank strainer that Bob mentioned, along with the rubber membrane inside the valve itself. Both are easy to do, but be very careful wrenching on the valve assembly - it's cast aluminum and very easily cracked. It has standard npt threads, by the way, so use Teflon tape to reinstall it. Just keep the tape away from the end of the pipe - you don't want that stuff getting into your fuel line.

Hopefully you don't have the diesel bugs that Bob mentioned - those sound like nasty critters!

 

[R Barger]

Checked fuel flow where line goes into the primer pump and have a good flow of fuel so I guess that shows the tank and strainer is ok. For the first 3 to 4 minutes the tractor only runs at 500 rpm and the throttle has no effect on it at all. Then all at once the engine picks up fuel and everything is normal. Could it be that the lift pump is slow to pump the fuel to the injector pump or the filter dirty? Is there a way of testing the lift pump?

 

[Bob Rooks]

The lift pump and priming plunger share the same check valves. If the priming plunger works, then the lift pump will work too. Did you pull the banjo bolt and check the little nylon screen? You should also be aware that there is no direct mechanical connection between the throttle control and the rack. The throttle handle only operates the governor. The governor is what controls the rack. Try pumping the priming plunger rapidly when the engine will not accelerate, see if it makes a difference. If not, then my previous speculation stands - sticking rack, governor issues.

 

[cleat]

I replaced my lift pump because it was leaking fuel into the injection pump, the little nylon screen, and the fuel filter on my DF254 a couple of months ago.

The nylon screen was partly clogged. Tractor always ran good before but now it accelerates under load much better.

This is the first time I have ever touched the fuel system aside from oil changes. Tractor has around 300 Hours.

Check the nylon screen on yours and replace the filter if you have not done so.

If the lift pump is bad, they are not too pricey.

 

[R Barger]

I have confirmed that I do have plenty of fuel to the injector pump. One thing I failed to tell in the original post is that when it is running at 500 rpm there is a stream of white smoke. When it picks up rpms the smoke goes away and it runs normal. Would low compression on one cyl cause the throttle not to have any affect on the engine.

 

[Bob Rooks]

White smoke that dissipates quickly means several things: Cold combustion chamber, coolant in combustion chamber, water in fuel. White smoke that lingers in the air is unburned fuel, and is usually caused by a dribbling (worn or dirty) injector.

 

[Bob Rooks]

Would low compression on one cyl cause the throttle not to have any affect on the engine.

No. Low compression on one cylinder would not keep the engine from accelerating.

 

[R Barger]

When you first start it it sounds like it's running on one cyl. When the rpms increase it is running on both cyl. I have opened the injector lines and confirmed is running on both cyl. I read something on one of forums about jinma's having some type valve to keep them from accelerating when cold. Have you ever heard of this?