20hp vanguard help please!

[beddy85]

My father-in-law has an agco Allis 1720h with a 20hp vanguard. The last few times using it just for light pulling work it will run fine then all of a sudden its like it's only running on one cylinder. This happens very sporadically no matter what throttle position it is in. Sometimes it will done it several times and the next I've not at all. I'm looking for any tips on what to check first. Thank you

 

[ILENGINE]

Get a couple of those cheap blink type spark checkers and put one on each spark plug and then when it acts up see if both are still flashing.

 

[slomo]

Dump and clean out the fuel tank and lines. Verify good fuel flow AT carb inlet into glass jar.