Seafoam is a cleaner. Auto part stores, marinas etc carry it. Think of it like Gumout/ STP fuel additive, with the exception that it actually works well. I swear lots of this stuff is just diesel fuel in a bottle, but I'm pretty un-informed on their chemical make up really... You can introduce it through the carb w/ the filter removed and use it in the fuel and oil. New oil is a great start. Marvel oil is a good lube for such things as well.

There is only ONE adjustment screw and that is supposed to be for IDLE only. I do not engage mower blades at IDLE, only at higher RPM. The new coil is junk. Will have another new coil Mon or Tues. Now have intermitent spark on one side, weak spark on other side. Old coil is corroded through in one area. I'm still trying to figure out how most are saying it's a carb mixture problem when there is nothing to adjust, and idle speed isn't the problem. I still say it's the coil...we shall see. All this trouble over this engine and not getting much gardening done! Invested a lot in this machine. New blades, belts, engine parts, plus a new cultivator and hitch system. I need it to be working....just only so much I can do with little money. Very exasperated now. Neighbor down the road has 2 MTD riders for $50. Or 1 1/2 rather. Engines are different but still Briggs. No idea how bad those are...or if one of those would even mount since they are single cylinder and mine is a twin. 16 hp on the one I believe. Thanks for bearing with me on this and your suggestions.

Reg unleaded fuel and it is pump fresh. All airbox and carb components were cleaned thoroughly before reassembly. Update - Changed the oil and Wix filter, was in stock at O'Reillys for $11.00. I changed all the fuel lines out with new high quality fuel hose and darned if it did not start kinking again right where it makes a 90 degree bend where it comes off the bottom of the tank. Butts against the frame work. I got some tightly coiled spring that fits very snugly on the hose and installed it over the bend, and a new fuel filter so that takes care of that. Ran it again for 15 minutes and almost right away it starts running rough and trying to cut out when in the tall grass and out of it but worse under load. I could feel vibration thru the steering wheel. Occasionally it would clear up. On my motorcycle forum we do what is called plug chops. Drive it til it starts running rough, kill the engine and pull the sparkies. They were both very carbon fouled. I did not notice any black smoke this go round though. Walt, I am liking your idea of running on one cylinder when it starts running badly. The reason I am thinking so is I grabbed the laser thermometer right after pulling the plugs and shot both cylinder heads on the inside of the vee. Left side is 210 deg, right side is 150 deg. This is a dead giveaway that the right cylinder is not firing but why is still arguable. I am convinced the right cylinder is losing fire at times. Overheating coil? I stuck the plugs in the wires and grounded the threads while cranking and got spark on both sides. ??? Back to the carb again? I guess I could swap the 2 coils around and see if the cold head switches sides. What do y'all think.

Hey, this is great stuff!!!! I had this problem with my Craftsman Lawn Tractor "it starts, runs, then turns off as soon as I take my foot off the brake. I read all your comments and ran out to my tractor. I then removed the 2 bolts holding the springs and seat switch, removed the seat switch from the housing unit but left it connected to the wiring. Then I put the housing back under the seat (without the seat switch in place) and laid the seat switch down under the seat. Now when I let my foot off the brake my tractor continues to run. The only thing is that now when I get off the tractor it continues to run but who cares. I always wished it wouldn't stop running when I got off anyway. Dreams to come true. Thanks guys for your wisdom.