What can cause a small engine to surge?

The most common reason for a surging lawn mower engine is a blockage in the fuel supply, but there are other possibilities:

• Bad gas.
• Bad spark plug.
• Dirty / faulty carburetor.
• Gas filter blocked.
• Gas tank blocked.
• Gas line blocked.
• Gasket vacuum leak.
• Manifold vacuum leak.

What causes small engine governor surge?

If the spring is set in the wrong position it can cause the engine RPMs to surge. Over time the spring can stretch out, causing the same engine surging. Often surging caused by the governor can be fixed by simply adjusting the governor spring. It usually only takes a small adjustment to correct the surging.

How does governor work on small engine?

To control engine speed, a mechanical governor uses gears and flyweights inside the crankcase to detect changes in the load and adjusts the throttle accordingly. This closes the throttle, limiting the air-fuel released into the engine. When the engine load increases, the crankshaft spins more slowly.

Can a transmission cause surging?

Surging. “Surging” is often a sign of contaminated transmission fluid. When your transmission becomes too polluted, your vehicle may begin to jump forward or fall back for no apparent reason. Again, a transmission fluid flush could be all you need to solve this problem.

What causes a lawnmower engine to rev up and down?

A lawnmower that hunts and surges may be experiencing something as simple as an airflow issue. If the air that the engine requires to run is blocked, especially sporadically, it can cause the engine to slow down. When the blockage moves or clears, the engine may suddenly rev up in response.

Why is lawn mower revving up and down?

A carburetor that’s incorrectly adjusted is a common cause of poor engine idling that results in hunting and surging. Fortunately, most lawnmowers have two screws that allow you to adjust the carburetor yourself. One screw controls the idle speed while the other adjusts the idle mixture.

What causes a small carbureted engine to surge while running?

There are numerous things that could cause a small carbureted engine to “surge” while running the key items to think of when troubleshooting an internal combustion engine is the three key factors an engine needs to run : fuel, air, and spark. Is the fuel fresh? Carb clean and flow of fuel in carb bowl clear of water and debris?

Why is my gas engine burning so much gas?

Either your gasoline is old/bad or the carburetor is improperly adjusted; that’s a classic symptom of an engine that’s burning a fuel/air mixture that’s just a little too “lean” (not enough fuel for the air). I can hear exactly that sound in my mind’s ear; I’ve heard it a thousand times. It may also settle down immediately upon being loaded.

How does a fuel Governor slow down the engine?

That slows the engine down, quickly and the governor may not be able to keep up, so it increases the fuel, which speeds up the engine, then the governor reduces the fuel; which slows down the engine………….. you get the picture. Under load there is usually enough “momentum” to moderate engine speed changes which the governor can easily handle.

What should I do if my Briggs and Stratton engine is overheating?

For Opposed Twin engines, Horizontal and Vertical, remove the bowl drain nut and blow air in that hole. 2. Leaking Intake Gasket. Check for a loose carburetor or mainfold connection at the block. All Briggs and Stratton engine 3 to 6.5 HP, check the intake manifold for cracking (may have to remove carburetor) or loose connection at the block.