Farm Pro 2420 Problem

[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?