Nikki Carb Rebuild and Repair
Article by Mark Trotta
Lawn tractor surging? It's almost always a carburetor issue.
The lawn tractor in this article is a John Deere LA110, powered by a 19.5hp Briggs & Stratton Intek motor with Nikki carburetor.
Nikki Carb Rebuild Kit
The carburetor rebuild kit can be bought in two qualities. Buying an original equipment carb rebuild kit from John Deere or Briggs is expensive (about 50 bucks). This is attributed to the expensive materials required to withstand the effects of ethanol gasoline. But if you switch to non-Ethanol for your small engines, the original manufacturer's kit is not necessary.
Aftermarket Carb Rebuild Kit
I purchased a Nikki carb kit from Amazon, which was much less than the O.E. kit. Having the engine model and serial number will help you select the right kit.
The carb master kit is for many applications, including Briggs & Stratton 11-HP to 19-HP Engines with Nikki carbs. There's about 30 parts in it and fits several different Nikki carb types.
Shop: Carburetor Rebuild Kit for Nikki Carb
The Nikki carburetor kit included everything shown in the picture. Out of the 30 different parts, I only needed about five of them to rebuild the carburetor on my lawn tractor.
Carb Removal
Removal and disassembly of carb is straightforward. I find it helpful to take pictures and/or notes along the way, particularly how the linkages attach.
Two Types Of Float Bowl Gaskets
There are two different configurations of float bowl gaskets and fuel transfer tubes. Once the float bowl is removed, you can see the visual difference between the two gaskets.
Soak the Carburetor
If the carburetor is really old and dirty, invest in a gallon can of Berryman's Chem-Dip. This stuff will dissolve the old dried-up remnants of fuel and remove sludge.
Shop: Berryman Parts Cleaner with Basket
Be careful with this stuff, it will eat plastics, puff up gaskets, and remove paint. You can soak the body and float bowl, but not the plastic float.
A little brushing with a nylon brush will help clean things up. Rinse the carburetor and parts with water and dry with compressed air.
After soaking it, you'll still need to run something through the small passages to clean out the stubborn junk. You'll be surprised at how much stuff comes out of the ports.
Shop: Carb Cleaning Brushes
When done with cleaning the passages, blow out with compressed air.
Nikki Carb Assembly
The carb kit came with a metal float needle to replace the original plastic one.
Although the outside dimensions of the plastic needle are different than the metal one, it works the same.
At first, I thought the small O-ring I needed wasn't with the kit, but it actually was. What caused the confusion was that the O-ring is considerably smaller than the plastic tube it goes around. Once I compared it to the other carb, I could see it fit by stretching around it.
Happy Ending
After the carb was reassembled and re-installed back on the engine, it started right up. I also replaced the gas filter.
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