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Nikki carburetor 2019 Kawasaki Mule SX KAF400

#1

M

MParr

This Mule has always run rich and carbon fouls plugs. It’s getting to where it will need rebuilding or replacing. Is there a replacement Walbro carburetor available for this Mule?


#2

StarTech

StarTech

Might be simpler to rebuild the carburetor and install a leaner jet.

You have a choice of 99, 102, 105, and 109 that leaner than the 112 that supposedly was factory jet.

Or order a new carburetor and leaner jet.

Might be trial and error on which one to use.


#3

M

MParr

StarTech said:
Might be simpler to rebuild the carburetor and install a leaner jet.

You have a choice of 99, 102, 105, and 109 that leaner than the 112 that supposedly was factory jet.

Or order a new carburetor and leaner jet.

Might be trial and error on which one to use.
Click to expand...
That’s what I was thinking. I’m going to try a few more things in the morning. I’m going to recheck the choke cable adjustment. I’m going to pull the cover off of the mixture screw and see if I can fine tune it. If that fails, I will put a rebuild kit in it and smaller jet. I was hoping there was a Walbro replacement.
Thanks.


#4

M

MParr

@StarTech
I think that I’ll order a #109 and #105.


#5

Scrubcadet10

Scrubcadet10

put a BPR4ES spark plug in it. I've worked on several 600 series mules that fouled plugs, went up to BPR4ES from the stockc 6ES and that usuallys fixes them.


#6

S

slomo

What is the jet size for high altitudes? I see no mention for an HA main jet.

Make sure the needle/seat holds at 7psi.

Carb float level?

How bad is the fouling? Pictures please.


#7

StarTech

StarTech

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


#8

M

MParr

Scrubcadet10 said:
put a BPR4ES spark plug in it. I've worked on several 600 series mules that fouled plugs, went up to BPR4ES from the stockc 6ES and that usuallys fixes them.
Click to expand...
I already have. It hasn’t helped.
I currently have Champion RN14YC in it.
I thought of putting a BPR2ES in it.
The carbon fouling/rich condition seems to be fairly common in these Kawasaki Mule SX KAF400.


#9

M

MParr

StarTech said:
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.
Click to expand...
Right, the #112 is the stock jet.
However, the Kawasaki FJ400D engine lists a #110 as the stock jet.


#10

M

MParr

slomo said:
What is the jet size for high altitudes? I see no mention for an HA main jet.

Make sure the needle/seat holds at 7psi.

Carb float level?

How bad is the fouling? Pictures please.
Click to expand...
Pretty bad. It’s done it for a while now. I’m going to tweak it a little and adjust the choke cable as described in the service manual.
If that doesn’t work, I will order the jets, gaskets, and a new needle. I may order a new float too.


#11

S

slomo

StarTech said:
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.
Click to expand...
Agree. Some carbs offer high altitude mains for less fueling at altitude. In this case we see a variety of sizes.


#12

M

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.


#13

S

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.


#14

Tiger Small Engine

Tiger Small Engine

slomo said:
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.
Click to expand...
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.


#15

M

MParr

slomo said:
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.
Click to expand...
I threw the old plug away.
The air filter is a new OEM Kawasaki.
I plan on ordering the parts shortly.


#16

M

MParr

Tiger Small Engine said:
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.
Click to expand...
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.


#17

S

slomo

Did you get this ironed out yet? What was the fix action please?


#18

M

MParr

slomo said:
Did you get this ironed out yet? What was the fix action please?
Click to expand...
I have been busy and haven't had a chance to order the parts.


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