Small Engines (Lawn Mowers, etc.): FH721V Kawasaki troubles, filter images, engine spec

Question
The FH721V is on a Husqvarna ZTH6125 ZTR and has 370 hours on it. Engine started to run poorly; kind of missing or sputtering. I changed plugs, checked coils, valves, flywheel key, all ok. Cleaned carb and found the #136 main jet partially clogged. Problem solved; no!! IT ran perfectly for approximately 30 minutes, then slowly started to loose power. I stopped and cleaned the plugs which were blackened and started it up and got another 5 minutes of good performance. It also seem to be smoking a little and the exhaust pipe is extremely hot. When its dark out you can see fire coming out of the exhaust pipe.

Answer
This is the number 1 most asked question I receive.  I have literally answered it 50 times.

Here is the actual Kawasaki bulletin on this problem.

Subject
Kawasaki has recently changed the carburetors
on the FH601V, FH641V, FH680V, FH721V from an
externally vented carburetor (Pic 1) to an internally
vented carburetor (Pic 2). Both of these carburetors
use different air filters, although the air filters look
identical except for the part number printed on
them.
Carburetor Air Filter PN A/F Difference
1 Externally
Vented 11013-7024
Calibrated to external
vent carburetor
mixture
2 Internally
Vented 11013-7027
Calibrated to internal
vent carburetor
mixture
If the 11013-7027 is installed on an external vent
carburetor, the engine will run extremely rich.
Because of incorrect part substitution, customers
may have installed the incorrect air filter, not
understanding the difference and cause running
problems.
Kawasaki Action
Kawasaki has added text to the tops of each air
filter explaining which carburetor it should be used
with. (Please see both air filter images.)
Eligibility
Engine Model Engine Spec and Serial Number
FH601V, FH641V,
FH680V, FH721V
All engines are eligible because
customers may have changed to
the incorrect air filter.
Dealer Action
1. Dealers must make sure that they understand
the difference between both filters.
2. Make sure to install the correct filter on the
correct carburetor.
3. When selling air filters to customers, make
sure they understand the difference between the
carburetors and air filters. Show the customers the
pictures in this bulletin for a better explanation.
4. Dealers should stock both filters to service
their customers.
Warranty Information
This bulletin is parts information notification, and
not warranty authorization.
FH601V, FH641V, FH680V, FH721V ENG 04-09
CORRECT AIR FILTER USAGE September 8, 2004
© 2004, Kawasaki Motors Corp., U.S.A. Page 1 of 1
FACTORY ENGINE INFORMATION
S
E
R
V
I
C
E
Pic. 1 Pic. 2
A. 11013-7024 Air Filter Image
B. 11013-7027 Air Filter Image
FOR USE WITH INTERNALLY VENTED CARBURETORS ONLY

You need an exrenally vented air filter.  It will say external only on the top.   Part # 11013-7024.  

You also need to find a new dealer.  This bulletin is about 4 years old and should be common knowledge to any dealer that's worth a damn.