Troy Bilt Bronco 2009 engine — Need help

[semimechanicman]

I recently bought a mower to fix, It is the Troy Bilt Bronco 2009. It has a 18 HP 597 CC Engine. I bought a new Carburator, new coil, new gas lines, new air filter, changed the oil, changed the spark plug. It runs perfect for about 30 seconds but then starts surging and that’s all it does until I turn it off. It is the only problem that it has, please help!!

 

[ILENGINE]

What happens if you start applying the choke, Does it smooth out or run worse. If it starts to smooth out as more choke is applied then you have a carb problem, or air leak in the intake system.

 

[semimechanicman]

What happens if you start applying the choke, Does it smooth out or run worse. If it starts to smooth out as more choke is applied then you have a carb problem, or air leak in the intake system.

Everything works fine, it idles fine and starts pretty fast. After 30 seconds it starts surging but doesn’t die.

 

[Richard320]

A wild guess, here. Could the fuel cap be too air=tight? No air in means no gas gets out, means fuel starvation. All you need to do to test this is run it until it starts acting up then loosen the gas cap.

 

[StarTech]

Everything works fine, it idles fine and starts pretty fast. After 30 seconds it starts surging but doesn’t die.

That didn't answer IL question

 

[semimechanicman]

That didn't answer IL question

It did, I said everything works fine which when I say all, it means even the choke works.

 

[semimechanicman]

A wild guess, here. Could the fuel cap be too air=tight? No air in means no gas gets out, means fuel starvation. All you need to do to test this is run it until it starts acting up then loosen the gas cap.

A wild guess, here. Could the fuel cap be too air=tight? No air in means no gas gets out, means fuel starvation. All you need to do to test this is run it until it starts acting up then loosen the gas cap.

Thanks, I will make sure to try that out.

 

[Rivets]

IL asked what happens when you apply the choke when the problem occurs? We understand that the choke works fine when starting, but want to diagnose a rich or lean running condition. I’ll ask the same question another way. When the problem occurs and you apply choke to the engine, is there any change to how the engine runs?

 

[bertsmobile1]

You are missing the point
Ilengine wants you to start applying the choke AFTER the engine starts to surge.
What he ( and the rest of us ) needs to know is weather the carburettor is supplying sufficient fuel to maintain high idle.
If you want help from us it will work so much better if you read the post carefully , do exactly what is asked then report exactly what the results were.

We are not there drinking your beer & looking, smelling & listening to your mower.
We are here on the end of a screen trying to do a diagnosis .
Otherwise what will happen is every one with a "pet" problem will chime in and you will be chasing your tail applying fixes for problems you do not have.

 

[semimechanicman]

IL asked what happens when you apply the choke when the problem occurs? We understand that the choke works fine when starting, but want to diagnose a rich or lean running condition. I’ll ask the same question another way. When the problem occurs and you apply choke to the engine, is there any change to how the engine runs?

Yes when I apply the choke with after starting the engine, it starts running at a low speed, like normal