18hp Briggs & Stratton surging?

18hp Briggs & Stratton that surges when at full throttle. It’s even worse when it’s under a load. I’ve had the carb rebuilt with no change in performance. Changed oil, gas and gas filter. Any ideas?



8 thoughts on “18hp Briggs & Stratton surging?

  1. I just had the same problem. The back of the carb is the air intake. It's not working right. Open it all the way by turning it to the right. This will give you max air flow. Mine runs good after I did that. I may force it to stay open. Try that and see if it helps.

  2. Ha! Mine is doing this also. I went on a search for some non-e gas, but no luck. There is 1 station where my bro lives, it is about an hour, so I will obtain it for next time. I'll live with it while I cut my "wheat field" today. That will keep the snitches from dropping a dime on me to the county!! Thanks for the tips!!

  3. i changed the carb on my 17.5 ohv with one from an 18 and had to readjust the throttle so that it closed of some choke (black plastic) and it worked.

  4. I have one doing the exact same thing. I emptied and cleaned the gas tank, put fresh gas in it, replaced the fuel filter, new fuel lines, a brand new carburetor, a new spark plug, cleaned the ignition points, and have a good blue spark at the plug. Anyone have any other ideas/suggestions? It's surging exactly like the video and backfiring as well. I also adjusted the valves to spec.

  5. Yeah, it's probably a tiny bit lean or rich. Turn that carb adjusting screw (with the plastic "stops" on it there in your video) one way or another (only about 1/8 turn at a time), and it should get it back going for you. HTH, Chuck

  6. Problem Solved. Drained gas and bought new gas with no ethanol. Still ran a little rough at first but then smoothed right out. There may be an additive I could have used, but I didn't check.

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