B & S 18 hp engine surging and popping.

[Forest#2]

Some carb info for your single cylinder Briggs engines with the Nikki carbs:
Briggs first used a Walbro LMT carb on those type engines as a more user friendly re-buildable carb.
Here is some info about rebuilding your Briggs/Nikki single barrel carbs. and parts link.
I get fast shipping from sawzilla and shipping is very reasonable.
You need to save your OEM Nikki carbs. You got lucky with the replacement. The China clone replacements are a roll of the dice.
Best to get them from Amazon for a free return refund with 30 days.
I've seen guys that sometimes have to get 3 before they get a good one. Also when replacing they usually require a static governor adjust be done.


For carb rebuilding: (also look at the Walbro LMT, they are a direct bolt on for the Nikki.
https://outdoorpowerinfo.com/repairs/

When looking for Nikki carb parts and you have a part number use Briggs as the part number instead of Nikki



Also for Briggs Nikki parts check out sawzill parts.com click on the menu link in the upper left corner and select Briggs for the Nikki parts list.

Stihl Chainsaw Parts | Husqvarna Chainsaw Parts | Sawzilla Partsct

 

[Forest#2]

and some links to rebuild you tube videos of the Nikki rebuild.
Nikki Carb Rebuild Single Cylinder Briggs - YouTube
and

Nikki Carb Rebuild Single Cylinder Briggs - YouTube - Bing

Intelligent search from Bing makes it easier to quickly find what you’re looking for and rewards you.

www.bing.com

 

[Air4Dave]

Thank you, guys, for all your help. After cleaning and adjusting everything several times. I cleaned and rebuilt 2 Nikki carbs (with OEM) parts the correct way. No change. I finally put a new Rui*ing carb on it and ran Hi-test fuel through it. It popped a couple of times then it smoothed out and ran like a sewing machine. Thanks again for your help.

I’m going to add just my .02 worth here and say that I run nothing but premium, ethanol free fuel in ALL my small engines. If you can’t get ethanol free at the pump you just run premium fuel and/or buy the ethanol free additive at an automotive store.

 

[Roy697]

Had a generator that I could not stop surging . Turned out one of the springs that works the throttle was bad.

 

[StarTech]

And it can even be bad spark plugs.

 

[Auto Doc's]

It sounds like you have a fuel issue.

Start at the fuel tank and work your way from there. Debris will collect in the fuel nipple over year of use where the line connects. Next would be the fuel lines and inline filter. Aged fuel lines get rigid and will come apart internally.

I recommend only good fuel line such as Gates brand or NAPA. Stay away from Amazon or Ebay fuel line. That stuff fails very easily with heat and Ethanol fuel blends. I purchased a bulk roll online and had to throw it away.

Next, if it is a v-twin, confirm both cylinders are producing power