Misfiring on one cylinder on my 14hp Briggs Vanguard Vtwin.

Hey my motor is a 14hp Briggs Vanguard Vtwin. It is straight piped to under the foot rests and exists in front of the rear tires. This motor has never let me down. My last mudding adventure, one cylinder started misfiring. It strarted doing it when i went through deep mud in 5th gear. It sounds like one cyclinder is working a lot harder than the other when i was going fast in the mud. then i would let out the clutch and they would both have the same tone again. Now i can hear the left cylinder missing at idle. That is the only time i can hear it, it still rips at max RPMs (governed). I am thinking i need to adjust my valves. I am really hoping that is all i need to do. If there is anything else you guys think it could be, please let me know. Thank you

If you haven't already, replace the spark plugs... That sounds like how my old 14 horse briggs acted when it was time for a new one (except it was a single so it eventually just died).

i replaced them last fall do you think i still need to replace them?

Yep.

ok that is easy enough but i should replace both right?
and what would cause this that i need to replace them so soon?

Yes do both, a little oil can foul them fairly quickly, the plug change is the first step, and easiest, in diagnosing a problem. Start with plugs and see if that takes care of it first.

couldnt i just switch the plugs and see if the other side misfires?

That's a decent idea for troubleshooting... You probably don't need to replace both at the same time IMHO.

it wasn't the spark plugs. Now it only leads me to think it is is my valves. That or i lost compression, but i am really hoping i can just adjust my valves and it will be fine. The reason i think it is my valves and not like the air filter or carb is becasue it only misfires on one cylinder. Please let me know what you think.

Can you check compression, do you have access to a guage? If both sides are close to the same, valves are probably okay.

ya i could probably come up with one i will check that then let you know thank you if they arent the same then would it be the valves?

That is a good possibilty.

I all of the years of running these engines, the only valve related issue I have ever encountered was a failed push rod on my 14 horse OHV single cylinder. If it was the same thing on your machine, I would think you'd have nothing from that side at all. Not saying your instinct isn't correct on this, but keep your mind open to other possibilities. Just some friendly advice from a guy who is a troubleshooter by trade

thank you very much what could it be then?

My guess? More likely a bad coil or something plugged up in the carb than valves.

You need some basic things for any engine to run.

Spark
Spark timing
compression
gas

If you have those, it will run. Unless you have too much gas, or something along those lines.

You have gas.
Compression, pull both plugs and put your finger over the hole while starting. See if both holes feel like they are pushing the same amount of air out.
Spark timing is right, otherwise the other cylinder would not fire.
Even if the spark plug is sparking outside of the engine, it may not fire under compression when installed.

First thing I would do is put new plugs in, regardless of how old they are. Plugs go bad.
If it is still missing, I would suspect the coil is shot.

Good luck

Does this engine have coils, or electronic ignition system?

it has coils