1967 John Deere 1020 will not run after 15 minutes of operation

[ehjiii]

Starts up and runs beautifully for about 15 to 30 minutes, then it begins to stumble and effectively stalls. Give it a few minutes to cool down (is not running hot) and it will start up and run. Since it is already at operating temperature, it takes less time for it stumble and stall again.
Thought it was vapor lock, so I got an electric fuel pump. Did not help. I rerouted the fuel line. Did not help.
Soaked and cleaned the carb. Did not help.
All ignition parts are new (3 months). To verify continuity of power, I ran a jumper from the battery to the coil. Did not help.
I’m out of ideas. If you have an idea, please assist!

 

[SteveS42240]

Wild thought, I know you put an electric fuel pump on it, but have you made sure your fuel tank is allowing the fuel to flow out freely? Does it go through a settlement bulb and is it clean and allow a free flow?

The other thought I have is a bad coil that is getting hot and breaking down.

Good luck with it.
Steve.

 

[jaxs]

There isn't a reason for this,another reason for that,one reason for those and others for,,,,,,,,,,,,,,,,,,,,,
The most seasoned mechanics have to TROUBLESHOOT to determine what is causing a malfunction. To get you off to a start remove breather tube from carb,start engine and stand by to squirt gas in carb when engine begins to stall. If squirting gas in carb doen't help it continue running the problem IS NOT with fuel. Put breather back on while engine isn't running and put a spark detector inline with any plug wire. Start and stand by watching RYTHEM and intensity of spark then see if rhythm and/or intensity changes as engine stumbles and dies.

Complete those then come back here to report outcome and we will pick it up from there.

 

[Ricn]

My old 1020 did this as well, found the gas tank was very, very dirty!

 

[Wagtail]

G'day Mate and welcome to TBN from Downunder.

What you describe is the classic symptom of a biological growth in your fuel tank. I know, as this happened to me.

If you put an inspection camera down into your tank, the growth (incorrectly called 'algae') will be at the bottom and will look like fairy-floss/cotton-candy mixed with phlegm . It may also be seen in your fuel bowl.

If so, you'll need to drain the tank and then apply a diesel 'biocide' (about 5 litres). Wait 24 hours, drain that and then clean/wipe out the tank (use a CHUX/J-Cloth on the end of a long 'grabber'). You'll need to 'blow out' the fuel line, clean the fuel bowl & change the fuel filter, at the very least.

Only then can you put fresh fuel in your tank and 'charge' your fuel system.

Not knowing where in the world you're posting from, I can't recommend a biocide to use... If you are from Australia/NZ, then I know of the perfect product to use.

Good luck and let us (TBN) know how it's going.

 

[square1]

Does it do this if you loosen the fuel tank cap? Symptoms are similar to plugged vent hole in fuel cap

 

[jaxs]

Starts up and runs beautifully for about 15 to 30 minutes, then it begins to stumble and effectively stalls. Give it a few minutes to cool down (is not running hot) and it will start up and run. Since it is already at operating temperature, it takes less time for it stumble and stall again.
Thought it was vapor lock, so I got an electric fuel pump. Did not help. I rerouted the fuel line. Did not help.
Soaked and cleaned the carb. Did not help.
All ignition parts are new (3 months). To verify continuity of power, I ran a jumper from the battery to the coil. Did not help.
I’m out of ideas. If you have an idea, please assist!

G'day Mate and welcome to TBN from Downunder.

What you describe is the classic symptom of a biological growth in your fuel tank. I know, as this happened to me.

If you put an inspection camera down into your tank, the growth (incorrectly called 'algae') will be at the bottom and will look like fairy-floss/cotton-candy mixed with phlegm . It may also be seen in your fuel bowl.

If so, you'll need to drain the tank and then apply a diesel 'biocide' (about 5 litres). Wait 24 hours, drain that and then clean/wipe out the tank (use a CHUX/J-Cloth on the end of a long 'grabber'). You'll need to 'blow out' the fuel line, clean the fuel bowl & change the fuel filter, at the very least.

Only then can you put fresh fuel in your tank and 'charge' your fuel system.

Not knowing where in the world you're posting from, I can't recommend a biocide to use... If you are from Australia/NZ, then I know of the perfect product to use.

Good luck and let us (TBN) know how it's going.

Wag do you reckon if he gets rid of the carburetor and those stinking ignition parts there will still be any need to mess with biocides?

 

[ehjiii]

Wow! Great response from a lot of guys. Thanks to all.
PROBLEM SOLVED…for now. Recall I said I had replaced all ignition components 3 months ago. I had a flawed mindset that it couldn’t be a new part from NAPA (Ha!). Put the timing light on it to see non consistent firing. Pushed on the new coil and the engine actually stalled.
Swapped it out and cut a large field with no issues. Fingers crossed.
Again, thanks to all for reaching out.

 

[Wagtail]

Good stuff and thank you for getting back to us with your result.