Nikki carburetor 2019 Kawasaki Mule SX KAF400

[slomo]

View attachment 69765
Jet for high altitude get smaller as altitude is increased. Note jet sizes are in hundredth of a millimeter. And they are usually marked.

Agree. Some carbs offer high altitude mains for less fueling at altitude. In this case we see a variety of sizes.

 

[MParr]

I went back over all of the adjustments to the choke, low idle, and accelerator stop. I also went to a BPR2ES spark plug. The valves have been adjusted to .005. The thing idles so smooth. It cranks really easy. I’m going to run it a while and check the spark plug for carbon fouling. I prepared to remove the carburetor and change the main jet, float, and needle. We will see how it goes.

 

[slomo]

I know these are simple mower engines. Running a super hot plug could lead to pre ignition pings. Probably never happen in a mower engine. Not enough load I would guess. I would stick to the stock heat range and deal with the main jet sizing down from 112.

Post up a pic or video of the fouling. Would give us an idea of how much smaller to go on the main.

Make sure she is not passing excess fuel from the needle. Float level the same. Choke plate wide open. Remove air filter for testing. I've had perfectly clean "looking" filters act like the choke was on. New air filter, she ran like a top.

 

[Tiger Small Engine]

I know these are simple mower engines. Running a super hot plug could lead to pre ignition pings. Probably never happen in a mower engine. Not enough load I would guess. I would stick to the stock heat range and deal with the main jet sizing down from 112.

Post up a pic or video of the fouling. Would give us an idea of how much smaller to go on the main.

Make sure she is not passing excess fuel from the needle. Float level the same. Choke plate wide open. Remove air filter for testing. I've had perfectly clean "looking" filters act like the choke was on. New air filter, she ran like a top.

Carbon fouling plug can also be a weak ignition coil(s). Going two plus heat ranges hotter on spark plug may not be the answer in a mower. More something that is done in an older two stroke quad or dirt bike.

 

[MParr]

I know these are simple mower engines. Running a super hot plug could lead to pre ignition pings. Probably never happen in a mower engine. Not enough load I would guess. I would stick to the stock heat range and deal with the main jet sizing down from 112.

Post up a pic or video of the fouling. Would give us an idea of how much smaller to go on the main.

Make sure she is not passing excess fuel from the needle. Float level the same. Choke plate wide open. Remove air filter for testing. I've had perfectly clean "looking" filters act like the choke was on. New air filter, she ran like a top.

I threw the old plug away.
The air filter is a new OEM Kawasaki.
I plan on ordering the parts shortly.

 

[MParr]

Carbon fouling plug can also be a weak ignition coil(s). Going two plus heat ranges hotter on spark plug may not be the answer in a mower. More something that is done in an older two stroke quad or dirt bike.

This is a Kawasaki FJ400D in a Kawasaki Mule. The carbon fouling is pretty common in these things.
The FJ400D is also used in EZ-GO golf carts and John Deere Gators. The standard jet for the EZ-GO is a #110 for sea level to 3,000’ above sea level. I will definitely need a smaller jet.