Tractor quit running. Air in fuel?

GManBart · Jun 2, 2016

TnAndy said:
Nope....the first step is make sure you actually HAVE fuel at the filter inlet. Otherwise, you could change it and it wouldn't make a lick of difference.

Once you determine there is fuel to the filter, yep....change it.

We already know fuel is getting to the filter inlet because he's able to manually prime and restart after it dies.

I plan fuel filter changes any time there's a fuel issue with a diesel. Once you're opening the system up, you might as well change them anyway. When you take the filter(s) off, you should know if you're getting enough fuel to them. Worst case...shut the supply valve/petcock, remove the filters, open the supply valve and see what happens. If the supply seems weak, then I look at the supply from the tank to the filter.

TnAndy · Jun 2, 2016

Both times I had a tank outlet blockage, I could wait a minute or two, the little electric booster pump would get enough fuel to re-prime the system (equal to a manual priming) and the tractor would start.

The bug in the fuel tank would jiggle off the fuel outlet (I know this because I finally stuck a Rigid inspection camera in the tank and watched it happen), and the tractor would run until the bug floated back over the outlet....shutting off enough fuel to kill the engine.

I changed the fuel filter initially, thinking the same thing. Took it to the dealer, where they replaced the electric fuel solenoid shutoff....twice....and were going for a third time until one of the mechanics noticed the fuel strainer bowl back at the tank was actually sucking INWARD (plastic bowl), and was empty as the main fuel pump tried to get fuel. He jerked the fuel line off the tank, and there was barely a trickle of fuel. Stuck a screwdriver up in the tank outlet, and got hosed with fuel ! That was at 150hrs.

Couple years later at 700hrs, same thing happened again. This time, I knew to look first at the tank outlet. Same thing....engine quit, remove line...tiny fuel flow. Got out the camera, looked in the tank...sure enough...a small wasp (dirt daubber we call them) right over the fuel outlet. Took a long grabber tool, along with the camera, removed it.....everything good again.

How did the wasp get in the tank ? I suspect my fuel fillup hose. I hang the nozzel on a hook pointing up....I think the wasp flew in, died, and when I went to fill up one time, I hosed it in the tank....can't figure any other way (line between fuel tank and nozzle has a 10 micron filter, so it didn't come via the tank) it could get in a closed tank. Only time the fuel cap is off, I'm standing there filling the tank. SO now I dip the nozzle down, bang it against the wall, let a little fuel flow out first before I fill the tank.

This may well NOT be the OP's problem......but having had it happen to me twice, I'm inclined to look at fuel flow FROM THE TANK first dadgum thing now.

GManBart · Jun 3, 2016

TnAndy said:
Both times I had a tank outlet blockage, I could wait a minute or two, the little electric booster pump would get enough fuel to re-prime the system (equal to a manual priming) and the tractor would start.

The bug in the fuel tank would jiggle off the fuel outlet (I know this because I finally stuck a Rigid inspection camera in the tank and watched it happen), and the tractor would run until the bug floated back over the outlet....shutting off enough fuel to kill the engine.

I changed the fuel filter initially, thinking the same thing. Took it to the dealer, where they replaced the electric fuel solenoid shutoff....twice....and were going for a third time until one of the mechanics noticed the fuel strainer bowl back at the tank was actually sucking INWARD (plastic bowl), and was empty as the main fuel pump tried to get fuel. He jerked the fuel line off the tank, and there was barely a trickle of fuel. Stuck a screwdriver up in the tank outlet, and got hosed with fuel ! That was at 150hrs.

Couple years later at 700hrs, same thing happened again. This time, I knew to look first at the tank outlet. Same thing....engine quit, remove line...tiny fuel flow. Got out the camera, looked in the tank...sure enough...a small wasp (dirt daubber we call them) right over the fuel outlet. Took a long grabber tool, along with the camera, removed it.....everything good again.

How did the wasp get in the tank ? I suspect my fuel fillup hose. I hang the nozzel on a hook pointing up....I think the wasp flew in, died, and when I went to fill up one time, I hosed it in the tank....can't figure any other way (line between fuel tank and nozzle has a 10 micron filter, so it didn't come via the tank) it could get in a closed tank. Only time the fuel cap is off, I'm standing there filling the tank. SO now I dip the nozzle down, bang it against the wall, let a little fuel flow out first before I fill the tank.

This may well NOT be the OP's problem......but having had it happen to me twice, I'm inclined to look at fuel flow FROM THE TANK first dadgum thing now.

Doing what I described would have found your insect problem. Close the fuel supply petcock, remove the filter, open the fuel petcock, check for flow before installing the new filter. Many tanks aren't exactly easy to check the fuel outlet, and most folks don't have an inspection camera handy, so they're forced into cracking a line at the filter inlet....at that point you're going to have to purge the system of air anyway, so you might as well replace the filter while you're at it.

I've dealt with fuel delivery problems many times over the years and they've all been either plugged filters, or failed lift pumps....no bugs in the tanks, although I know it can happen.

I plug the end of my fuel nozzle with a rag before I put it back on the tank

rutwad · Jun 3, 2016

I haven't done much with it until this morning. I checked voltage at plug for in-tank pump and read 6v. I'm assuming that's correct because the tractor started. Clear water-in-fuel bowl on filter always stayed full with no indication of air or lack of fuel. Tractor idled for 10 minutes. Went up to 1300 for 10 minutes. 2000 for 10 minutes. I had almost decided whatever the problem was went away, but at wide-open throttle it ran about 5 minutes and shut down. Up until this point the tractor ran great, then shut down just like I switched it off. Temperature was fine. It again restarted after turning over more than normal and manually priming it. I cranked just to see then shut it down. 2 hours later I went back. Manual primer is tight but tractor would not crank as it easily as it should so I went ahead and pumped it a couple times. Cranked up and went to wide-open throttle. It ran 15 minutes and shut down. Temp gauge read normal. Fuel bowl full. Manual primer tight. Tried cranking and it again turned over more than normal without cranking, so I quit since the problem seemed to be the same.

rutwad · Jun 3, 2016

Just went back and opened fuel cap, primed, and again it's not starting.

rutwad · Jun 3, 2016

A quick look at my operator manual says it has a mechanical lift pump so the 6v must have been for the fuel gauge

TORQUIN · Jun 3, 2016

I went through something like what TnAndy described, but my ZD25 mower didn't cut off most of the time, it just lost power in a big way and most of the time I could idle just fine, but WOT was a no go. I pulled fuel lines and verified flow, changed filters and could not find the problem, until I pulled the tank and found some alien globs of goo hanging around in the bottom of the tank. They'd get sucked into the pickup tube slow or cut off fuel flow but after letting the mower sit for a few minutes they'd drop out and float around a while longer until they found their way back into the pickup tube.
I'd pull the tank unless you can drain it and look inside with a camera. You have received good advice in this thread. Go though it step by step and you'll find the problem.

Chris

GManBart · Jun 3, 2016

rutwad said:
A quick look at my operator manual says it has a mechanical lift pump so the 6v must have been for the fuel gauge

Not to be too blunt, but people have offered advice, and asked you questions, but it doesn't appear you've answered them, or attempted any of the diagnostics suggested. Are you looking for help, or to just report what you're experiencing?

From the description of what's happening, it's likely a classic case of the lift pump failing. The pump has I've seen the exact symptoms happen four times now on Perkins engines with the same style lift pump. Looks like this:

MASSEY FERGUSON FUEL LIFT PUMP 4222449M91 422476M91 4225162M1 - GD FUEL LIFT PUMP LTD.

rutwad · Jun 3, 2016

I have good fuel flow, as suggested. Tank is venting, as suggested. Blockage in tank, haven't checked. Fuel filters, haven't changed. I haven't been into town where I could purchase any.

GManBart said:
Not to be too blunt, but people have offered advice, and asked you questions, but it doesn't appear you've answered them, or attempted any of the diagnostics suggested. Are you looking for help, or to just report what you're experiencing?

From the description of what's happening, it's likely a classic case of the lift pump failing. The pump has I've seen the exact symptoms happen four times now on Perkins engines with the same style lift pump. Looks like this:

MASSEY FERGUSON FUEL LIFT PUMP 4222449M91 422476M91 4225162M1 - GD FUEL LIFT PUMP LTD.