My Farmall 400 started great, idled great, but stalled under load. This would happen within the first five minutes. I replaced the spark plugs, spark plug wires, and distributor cap, but that didnt help. I was thinking of replacing the coil, but the astute folks on this forum told me it sounded more like a fuel flow problem. They were right!
Special thanks to @DeltaRed, who suggested that I open the drain plug on the carburetor to check for good flow. I ultimately discovered the cylindrical screen fuel filter was partially plugged. After cleaning the filter, the tractor runs great under load now.
For any other neophytes like me, Ill describe in more detail. When I opened the carb drain plug, first a gush came out as the carb emptied, then a steady stream of gas. I read on another thread that the stream should be able to fill a pint in less than three minutes, so I timed the flow. It was half a pint in three minutes. I then did the next easiest thing and removed the sediment bowl and gas poured out of the tank, so I knew the problem must be between the tank and carb.
To remove the fuel line at the carb, loosen the outer smaller nut while holding the larger nut next to the carb. The outer nut should rotate freely over the fuel line. If stuck, try PB Blaster or similar. Pull the fuel line out, then loosen the larger nut next to the carb. Pull this nut straight out carefully because a delicate cylindrical screen filter is attached to the end of the nut and this filter protrudes into the carb. I cleaned the filter, blew air through the fuel line, and put everything back together, though it was difficult to get the threads to grab. At first the tractor didnt run well, so I turned it off, opened the drain plug on the carb and drained some gas through the carb. After that, it ran great. Must have been some air in the line.
Thanks again to those who redirected me to fuel instead of electrical. Its because of you that my tractor runs great again!
Special thanks to @DeltaRed, who suggested that I open the drain plug on the carburetor to check for good flow. I ultimately discovered the cylindrical screen fuel filter was partially plugged. After cleaning the filter, the tractor runs great under load now.
For any other neophytes like me, Ill describe in more detail. When I opened the carb drain plug, first a gush came out as the carb emptied, then a steady stream of gas. I read on another thread that the stream should be able to fill a pint in less than three minutes, so I timed the flow. It was half a pint in three minutes. I then did the next easiest thing and removed the sediment bowl and gas poured out of the tank, so I knew the problem must be between the tank and carb.
To remove the fuel line at the carb, loosen the outer smaller nut while holding the larger nut next to the carb. The outer nut should rotate freely over the fuel line. If stuck, try PB Blaster or similar. Pull the fuel line out, then loosen the larger nut next to the carb. Pull this nut straight out carefully because a delicate cylindrical screen filter is attached to the end of the nut and this filter protrudes into the carb. I cleaned the filter, blew air through the fuel line, and put everything back together, though it was difficult to get the threads to grab. At first the tractor didnt run well, so I turned it off, opened the drain plug on the carb and drained some gas through the carb. After that, it ran great. Must have been some air in the line.
Thanks again to those who redirected me to fuel instead of electrical. Its because of you that my tractor runs great again!
