Backfiring through the carb or through the exhaust? Carb is too lean, exhaust is too rich.

Possible you over oiled the pre filter restricting the air flow. Might have over oiled enough to get oil on the paper air filter and that will really restrict air flow. So will water left in the pre filter when cleaning. Pull the pre filter off and see if the tractor runs better. If it does then you're on the right track. If it doesn't then remove the paper air filter and inspect it for signs of oil or water from the pre filter... in order for the air filter to work it has to be dry. Cleaning pre filter is pretty simple... warm water and a little dishwashing liquid. Wring it out carefully when clean and let it air dry. Some L&G manufacturers call for lightly oiling the pre filter and some do not. Read your tractor manual. Also might want to get the engine manual from the engine manufacturer and see what they recommend for servicing the filter.

These, in theory aren't awful to do. The problem comes in that EVERY one I have done, the drive pulley on the crankshaft will not come off. The solution is to remove the engine bolts and shift/ lift the engine to get clearance as the over qualified engineers built the guide into the frame pan. I pull the hood and lift the tractor- could be done w/out. PTO clutch/lock bracket comes off, deck comes off, 4 engine bolts(1 of the 4 engine bolts have to come off in such a way that one of the steering links need to come off.)Omit the last part if your pulley actually does come off. The rest is roll the belt over the front pulley, then the back fan/ pulley- then through the two pulley actuator and over the tensioner pulley. Like bakin' a cake... Impact wrench is a great idea to remove the PTO clutch. Re-apply loctite to the bolt when installing. 954-0461 I believe is the correct belt. Look under the hood for the part # to be sure.

You might want to contact the person that made this post some time ago in GW. Shot Here is a link that might be useful: PROBLEM WITH AGS 2140