Whats it mean when the engine hesitates when revving the engine?

[ryan3690]

I'm having a problem when I throttle the engine, it dies for a second and then revs up. Not sure if it a carb thing or not. The motor is an 18hp briggs. Any ideas would be great.

Thanks
Ryan

[Twizted1]

I'm having a problem when I throttle the engine, it dies for a second and then revs up. Not sure if it a carb thing or not. The motor is an 18hp briggs. Any ideas would be great.

Thanks
Ryan

It could be a few things. I would start with the fuel filters and or air filters. That would be a good start.

[jerseybigfoot]

It's a common problem. Typically a governor issue. The governor does not meter the throttle well off idle and tends to open the throttle 100 % before it goes back to the throttle position you want.

[Tomo]

hi ,
There are many items that can cause flat spotting ,stuttering

First the engine must be in good health
eg compressions
plugs good
air filter good
valve clearances adjusted

Adjust governor as per engine manual --u will need a non contact infared tacho $ 20-30

Then check fuel system
change filter
tank rusty inside ????? clean out or new tank
hoses change
carby strip and clean ,check float needle and seat , set float height

Spray carby cleaner fliud around the manifold to cylinder head connection to check for a vacumn leak . If a leak is present the engine will change rpm .

Then do a leak down test on each cylinder to determine if u have poor sealing either rings valves etc

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The factory top ring is pathetic,the depth or the width is narrower than the second ring and installs into the piston very shallow. This creates a ring thatvibrates/flutters .Ring seal is compromised at the bore face .
DUE to the poor installed depth into piston ring seal is also not the best .

Ring seal is very important
There is no mechanical pump on the carby
The fuel has to be sucked out of the carby eg create vacumn
IF THE CYLINDER HONE MARKS ARE NOT PERFECT THE CYLINDER WILL NOT SUCK CORRECTLY
THE ABOVE CAUSES FLAT SPOTS

Remember the Briggs Vanny or any other similar engine were never designed to accelerate

Have the cylinder block profesionally honed in an engine shop

hope this helps
tomo