Old-ish B&S MTD splitter only runs for 30 seconds

[Ahoragi]

12J702-1739-D1 Yard Machine Gold Series 27 ton​

Bought it from a guy on FB. It has a cracked gas tank that only allowed you to fill it half way or else it would leak out. It ran like a champ through 6 facecords of splitting. Suddenly it just started stalling out after a few minutes. I would restart and continue splitting till it shut down, rinse and repeat. I decided to take the carb out and spray out all the ports with carb cleaner and also emptied and cleaned the bowl. I rtv'd the gas tank closed so it no longer leaks. Now it only runs for 30 seconds and shuts down no matter where the throttle is. (same gas from same can bought two months back and has Ethanol Shield in it)

I ordered a replacement carb but any other thoughts or suggestions?

Thanks

 

[NickW]

Check the breather cap or breather tube for the gas tank. If whichever it has is plugged or non-functional it will create a vacuum as fuel is used, although I would think it would take longer than 30 seconds to build enough vacuum to kill it. Check the air filter. Anything that could restrict air or fuel flow. Plugged, cracked or pinched fuel lines? Plugged fuel filter?

 

[Ahoragi]

Check the breather cap or breather tube for the gas tank. If whichever it has is plugged or non-functional it will create a vacuum as fuel is used, although I would think it would take longer than 30 seconds to build enough vacuum to kill it. Check the air filter. Anything that could restrict air or fuel flow. Plugged, cracked or pinched fuel lines? Plugged fuel filter?

There doesn't seem to be a breather cap or tube anywhere. I ran it without the air filter and same result. Fuel flowed out of the fuel line just fine and there is not a fuel filter on this model.

 

[NickW]

Air has to be able to get into the gas tank somewhere. Unscrew the gas tank cap so it isn't sealed tight and see what happens. Some of those gas tank caps have rubber breathers in them that go bad or get plugged. If you fixed that crack in the tank maybe it wasn't getting air through wherever it should have been coming from.

 

[Ahoragi]

Tried that and same result, dies within 30 seconds.

 

[NickW]

Hmmm. I guess next step is install the new carb when it arrives and see what happens. Good luck! I just had a similar situation with my "new to me" splitter. One of the issues was something partially clogging the fuel inlet elbow at the carb.

 

[mark cline]

When it suddenly dies , pull the spark plug to see if you have spark . Does it restart immediately after it dies?
Also, most gas tanks have a fine screen in the fuel outlet, it gets crud on it that eventually reduces flow, just a few things that come to mind.

 

[Dieselhead]

Old spark plug or coil could be suspect, when it heats up shorts internally and kills the engine.

 

[Jags]

For a couple of bucks, Harbor Freight sells an inline spark tester. It's basically just an inline light bulb. Put this in line to your spark plug and when it dies notice if you are getting spark or not