Ford 881 starts up, abruptly dies.

[sleuth]

I recently replaced the fuel shutoff valve on my Ford 881. Tractor was running good before, but I noticed the valve was leaking so I replaced it and the leak is stopped.

However, after running ok for a couple days after that, my tractor is starting up fine, but abruptly dies anywhere for 5 seconds to 30 seconds after start-up. I've checked my fuel line for rust, and I have good flow of fuel all the way down to the sediment bowl for sure. I did add an inline fuel filter a couple years ago but again, I've got good flow all the way from the tank to the sediment bowl, so that makes me think it's not a fuel issue.

If that's true, then the other culprits would have to be either air or spark, right? Could it be time for new spark plugs?

 

[bcp]

I'm thinking it is running until the carburetor bowl is empty. Maybe obstructed or stuck needle valve or bad float? Is there a filter or screen at the carb inlet? Maybe your valve change loosened some particles that are now an obstruction.

Bruce

 

[Dollar Bill]

A fuel delivery problem should allow the tractor to run longer than 30 seconds before quitting. It's always best to check fuel flow from the drain plug on the bottom of the carburetor. Let it flow for about a minute to allow float bowl to empty. Should be steady, no drips.

Running for such a short period as yours makes me suspect a faulty condenser. Start it up - When engine quits, immediately pull spark plug wire and check for spark.

 

[Ford850]

Are you sure you have the new shut-off valve all the way open, and not at a reserve setting?

 

[sleuth]

A fuel delivery problem should allow the tractor to run longer than 30 seconds before quitting. It's always best to check fuel flow from the drain plug on the bottom of the carburetor. Let it flow for about a minute to allow float bowl to empty. Should be steady, no drips.

Running for such a short period as yours makes me suspect a faulty condenser. Start it up - When engine quits, immediately pull spark plug wire and check for spark.

Thanks. I'll have to get an assistant to help because it doesn't run long enough for me to jump off and get to the spark plug wire.
So if we have spark, does that point then to the condenser?

 

[sleuth]

I'm thinking it is running until the carburetor bowl is empty. Maybe obstructed or stuck needle valve or bad float? Is there a filter or screen at the carb inlet? Maybe your valve change loosened some particles that are now an obstruction.

Bruce

Had the carburetor rebuilt a couple years ago. How would you fix the obstruction?

 

[sleuth]

Are you sure you have the new shut-off valve all the way open, and not at a reserve setting?

This is the valve I have. As far as I know there is no reserve setting. I have it open all the way (without going against the hard stop because apparently fully opening the valve damages the o-ring and causes them to leak).

Fuel Shut-off Valve

 

[kuschneider]

Just read up a bunch on rebuilding a marvel schebler carburetor. You can find videos on Youtube as well. Not terribly hard to do at all.

 

[kirkawilson]

Other troubleshooting options are discussed here: http://www.tractorbynet.com/forums/parts-repairs/148847-ford-800-series-fuel-problem.html

 

[Dollar Bill]

Thanks. I'll have to get an assistant to help because it doesn't run long enough for me to jump off and get to the spark plug wire. So if we have spark, does that point then to the condenser?

You could use a spark tester to verify spark from the operator position.



If you are loosing spark, the condenser is your prime suspect. If you have an analog VOM, you can test the condenser as follows:

1. Discharge the condenser by disconnecting the lead and shorting it to the condenser case.

2. Using an analog Volt Ohm Meter; select X1 on the ohm scale.

3. Connect one VOM lead to condenser wire and touch other VOM lead to condenser body.

4. If the condenser is good, the meter should swing from 0 ohms to infinity as the VOM charges the condenser.