Running on 1 cylinder

[Dpak]

Hello
Motor running on 1 piston have changed the coil packs and the spark plug and left hand piston still not working I have changed the coil packs from left to right along with the spark plug and legit hand piston still not firing any ideas.

 

[ILENGINE]

Have you removed the valve covers to make sure the push rods are still in place and the valves are opening and closing properly. And the piston is moving up and down when the engine cranks.

 

[outdoorpowermike]

What engine is it? Make, hp?

 

[Rocky J]

Hello
Motor running on 1 piston have changed the coil packs and the spark plug and left hand piston still not working I have changed the coil packs from left to right along with the spark plug and legit hand piston still not firing any ideas.

If it is a Briggs you might also try unplugging both coils kill wires and try it again. Each wire has its own diode in it and they do go bad . It can have spark on both cylinders but one side at the wrong time / open ex valve piston on bottom of stroke .

 

[Freddie21]

Rocky has good idea and checking the valves is also good. Do a compression test on both cylinders and compare each.

 

[Laabk2]

Pull the plug on the left cylinder and make sure the piston is moving, had a twin on a JD that ran but seemed to have a miss. Everything checked out as far as firing and but still had a miss. Pulled the plug and found out the rod had broken.

 

[Gord Baker]

Hello
Motor running on 1 piston have changed the coil packs and the spark plug and left hand piston still not working I have changed the coil packs from left to right along with the spark plug and legit hand piston still not firing any ideas.

High tension lead from coil is likely faulty. Replace coil and wire. You should check compression first.

 

[Forest#2]

What engine is it? Make, hp?

Engine model, type and code?????????????

 

[Freddie21]

Bad wire, then the problem cylinder would follow the coil's placement. Coils were said to be replaced.

 

[Dwstwrt]

This may sound strange but I had a fellow bring me a Kubota zero turn mower with Briggs vertical twin that was only running on one cylinder as evidenced by using a laser thermometer on the exhaust Pipe. Working cylinder would hit 400 degrees in short order while non-working would hit barely 200 degrees. Long story short, after checking valves swapping coils from one side to other to no avail, cleaned the carb and problem was solved. Apparently, the carb has two circuits, one for each cylinder. Good Luck.