TN70D Will Not Start

[appalachian]

I filled up last night and drove home (2 miles). This morning, the engine started fine at 25 degrees, I let it warm up a bit, and on the way to the barn it started to die. For awhile it would keep running in idle, but finally died completely. I opened the filter/sump drain and pumped the manual fuel pump lever. About a half cup of fuel, with a little water, came out and then no more would pump out. Assuming there was frozen water in a line, I came back when the weather warmed above freezing, and pumped again, this time getting the same, about a half cup and no more would pump out. I can tell that there is no fuel to be pumped. I could only assume that the new fuel had water in it, but it ran fine during the 2 mile drive home. I have to go to church this afternoon and will see if it will pump or start when I get back (the outside temp will be near 40 by then), but if it doesn't, I don't know what to try next. I don't have a fuel system schematic. Any ideas? Thanks.

 

[George2615]

If you think there is water in the fuel, the best thing to do is drain that fuel from the tank then refill with good fuel and re-prime the lines. It wouldn't hurt to put some additive in the fuel such as Power Service (white or red 911 bottle) to remove water. You may have to bleed the lines at the injectors to get any remaining water that is in the lines out.

 

[RickB]

At 25 degrees most water is ice. New fuel filter, treat fuel, get the water out after thawing the ice.

 

[appalachian]

Thanks for the tips! On a TN70, does the fuel go from the tank directly to the pump, and then to the filter, or is there something else in-between? Is there a check valve or electric shutoff valve somewhere to prevent fuel from draining out of the injector lines?

The tractor is aging and our local dealer closed this summer. I think I'm going to have to bite the bullet and buy a service manual.

 

[MikePA]

Go to Messicks website and look your tractor up. They have parts diagrams that show a lot of this.

On my tractor, it's Tank---ShutOff(at the filter)---Filter---Pump---Injectors.

You could also learn a lot by just tracing the fuel route starting at the injectors.

To change the fuel filter on my tractor;

1. Close shut off
2. Unscrew fuel filter bowl
3. Clean bowl
4. Replace filter
5. Open Shut off
6. Bleed air out at pump
7. Done

The TN70D doesn't have a bowl, just a spin on filter, part number 98439682, $49.68.

 

[appalachian]

Thanks for the tips Rick and Mike. The outside temperature climbed into the 40's with sunshine early today, so I just left it alone until afternoon to make sure ice, if any, would be melted. It still would not start, so I began by removing the filter and pumped out about a half gallon of fuel. The filter was dirty, but not likely dirty enough to have caused the problem. I replaced it anyway. There was maybe 2 tablespoons of water that I got out of the fuel system, and that was from the filter yesterday. That could have accumulated over time and settled in the bottom of the filter. The TN70 fuel filter has a built in drain to remove water and dirt that settles. There's not a shutoff valve to close to change the filter. Just shut down and remove it with a bowl to catch spill. Screw the new one on, loosen the vent screw on top of the filter housing 2 turns, and press the manual pump lever on the bottom of the fuel pump until fuel comes out of the vent, and close it. I did everything today, but still no start, so I loosened one of the injector lines and pumped to bleed it. Fuel immediately came out, so I tried another start. This time it started, ran rough for a few seconds, and then all cylinders recovered

I honestly can't say what the problem was, but when I would pump with the manual lever, it would only pump fuel at the very end of the stroke. After one of the attempted starts today, it started pumping at about half stroke. After the last failed start attempt (before I bled the injector line) the lever started pumping fuel the entire stroke. The fuel that pumped out, and into the filter (that I was catching in a jar) did not have air in it, so unless there was trapped air in the pump, that wasn't the problem. I don't know what it was.... except that I had some late hay in windrows and 100% chance of rain forecast for tonight! Got it in just in time.

 

[trmechapt]

Could be trash in the fuel tank blocking the fuel from coming out of the tank. A test would be to unhook the line coming from the tank and blow back into the tank. Then see if the fuel flows better.
Gary

 

[appalachian]

I wondered about that too, Gary. I don't know if my tractor has a screen on the inlet, or a standpipe to pull fuel at a point above the bottom, or both. The manual pump lever is located on the bottom of the fuel pump, and it pumps fuel from the tank to the filter. However, I don't know if the engine driven part of the pump routes the fuel the same way. If so, and if there is no screen in the tank, it could have been trash hung up in the pump. It's impossible to follow the fuel lines because hydraulic, coolant, A/C and fuel lines, along with wire bundles are packed tight and clamped together. Anyway, once it started, it ran fine the rest of the day. It's past due for a tank clean out, but hopefully it will go 'til Spring.

 

[JWR]

If I followed all the narrative, it seems to me that: Water was the main problem. The tractor had been coping with it until enough collected somewhere to freeze. The high pressure pump will not move water anyway and you need to be sure water is excluded before it ever gets there. You could lose a pump and many hundreds of dollars that way. Once the water removal and drain plug actions were over with, I think you just needed to prime the system from having gotten air in it. Once you got an injector line off and primed that one, the engine was probably running on 2 or 3 cylinders and just cleared it's own throat from then on. Just luck you did not have to bleed all the injector lines. I'd certainly run some water seeking additive in it for a while and get out any residual water droplets left here and there. Then use your drain plug more often from now on ... it's hard to tell if you got water in the new load of fuel or had already been carrying it around. If you have an electric fuel pump it should be self-priming and you ought not have to be cranking that priming lever all the time. All this might be complicated by some air leaks here and there in the lines too.