John Deere M suddenly develops "issue" with fuel s

Over the past several months, I restored a John Deere M wide-front that my father-in-law bought new. Last week, I mowed a couple of acres with it using a Woods belly mower that this tractor has had used since the 70s.

It ran great then, as it did when I started it various times during renovation. It has new battery and it cranks and starts strongly.

Then, this week, it would start, run anywhere from 2 minutes to 30 seconds, then quit running. The plugs were fouled. Last week was the first time I put a load on the engine.

Suspecting too rich a mixture or maybe debris in the fuel, though I put all gas through a paint strainer and saw no gunk in the sediment bowl, I did the following:

Removed the carb, cleaned it (it was not very dirty and I rebuilt it during the restoration with new gaskets), put in fresh spark plugs, removed and checked the new sediment bowl assembly, then drained the gas tank.

After I put it all back together, I set the idle screw and load needle to settings recommended in the JD M manual. Today I added fresh gas, opened the fuel shut off, and watched the sediment bowl fill (a bit too slowly!).

The only way the tractor would run would be to add a bit of fuel into the air cleaner. The tractor idles well but when that fuel is gone, the tractor sputters and dies.

I'm going to run an aux tank into the carb to see if it runs well from that. If so, what should I do next?

Thanks for your advice!

Joe

Blow out the fuel line? Anything floating in the tank? Install a standpipe in the inlet of the sediment bowl.

I agree with post below, may have to blow air up through where fuel enters sediment bowl. I have to do that occasionally on my SMTA. Have taken tank off and tried to flush and all but once in a while something plugs the opening to sediment bowl. Hadn't had it happen for a couple years then did it again on first cutting. It has a stand pipe up into the tank. On Ih at least sediment bowl seems to fill slowly with lines hooked up to carb, sometimes won't fill completely until you start tractor, air in lines I guess. There is also a screen on the fitting that goes into the carb so you might check that.

I think you may have more than one issue. Paragraph three points to an ignition problem. Points, condenser, timing, wires, rotor or cap. Check them all and change the condensor. Too rich would be blowing smoke.
Paragraph 5 - Did you clean the screen in the fuel line elbow at the rear of the carb? Use brake or carb cleaner to do it as well as the screen in the top of the sediment bowl. Do that even if you can see through it.
Paragraph six - If it's filling slowly there an obstruction or it has an unvented cap. I once chased a small stick rolling around in the bottom of my tank for six month's in mine before I found and removed it.

I agree blow out the fuel line. I worked on a IH that would idle but not run. Took the fuel line off and blew through it. Had stuff come out that I had never seen in a fuel line before.

(quoted from post at 14:22:56 07/05/15) I agree blow out the fuel line. I worked on a IH that would idle but not run. Took the fuel line off and blew through it. Had stuff come out that I had never seen in a fuel line before.

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Fuel line was clear (it's new line, but I put cleaner through it and blew air through to confirm) and the fuel flow out of the tank into the sediment bowl was good once I removed the fuel line from the carb. Then I found a problem. It may be THE problem.

At the elbow where the fuel line enters the carb, the screen on the end of the elbow was moderately gummed up. I cleaned it and got good fuel flow into the carb. Visual inspection with a probe light into the tank shows no rust, but my range of vision is pretty small.

Tomorrow I'll put it all together and try to run the tractor a bit, after I install a standpipe screen above the sediment bowl inlet. Might as well. I have one from a different sediment bowl assembly.

If the problem recurs it's back to considering other advice given: condenser and coil or other issues. The M ran great for two hours a week ago, then got parked with about a gallon of fresh gas in the tank. I burn only non-ethanol gas in all the machinery and small engines on our farm.

So for now I'm going to focus on the fuel system. Last week was the first time the machine was put under any load since the fall, when I began working on the tractor.

Thanks to everyone for the advice!

Good idea about the condenser and cap. Both are old. I inspected them and all "looks" fine, but we know how that goes. The spark-plug wires are 2 years old.

It blows no black smoke other than a bit when starting. Then it idles well until it quits.

Update: it runs great. I put a standpipe above the sediment bowl (which now feeds fuel normally). Reinstalled the carb, setting idle screw and load needle to specs recommended by JD.

Started RIGHT up and ran great off fresh gas in the tank. Let it run about 10 minutes, shut it down, checked battery, ran again for a similar period.

Thanks to everyone who replied with good ideas. I'm sending my friend with a sometimes wonky IH Super A over here for advice and parts.