My kawasaki 23 hp model # fr691v on a toro 50 inch ztr from home depot started back firing. there was dirt in fuel filter so I changed it. changed the plugs and new air filter. Cleaned the carb. now thw backfiring stopped and it revs high to low, high to low. what causes this? a jet stuck?

Anti afterfire (carb fuel) solenoid is suspect. If it has a removable plunger take it out to test if problem goes away. Else snip off the plunger with a pair of side cutters.

The only caveat with this test method is if the magneto kill circuit is not functional you'll need to choke out the air intake or pull the spark plug wires to stop engine.

Specifications

Engine HD45

Engine Model Number(Kawasaki FC420V
Horsepower (10.5 kW (14 hp)
Displacement (423 cc (25.8 cu.in.)
Crankcase Capacity w/o oil filter (1.3 L (1.4 qt.)
Crankcase Capacity with oil filter (1.6 L (1.7 qt.)
Spark Plug-Gap (0.64 mm (0.025 in.)
Spark Plug-Torque (20 N·m (15 lb-ft.)
Cylinders (One
Stroke/Cycle (Four
Lubrication (Full-Pressure
Oil Filter (Standard Single Element
Air Cleaner (Dual Stage

Engine HD75

Engine Model Numbe(Kawasaki FC540V
Horsepower (12.7 kW (17 hp)
Displacement (535 cc (32.6 cu.in.)
Crankcase Capacity w/o oil filter (1.6 L (1.7 qt.)
Crankcase Capacity with oil filter (1.9 L (2.0 qt.)
Spark Plug-Gap (0.64 mm (0.025 in.)
Spark Plug-Torque (20 N·m (15 lb-ft.)
Cylinders (One
Stroke/Cycle (Four
Lubrication (Full-Pressure
Oil Filter (Standard Single Element
Air Cleaner (Dual Stage

Fuel System

Fuel (See Fuel in the Service Miscellaneous section
Fuel Filter (Single Stage, 60 Micron
Fuel Pump (Vacuum Operated-Diaphragm
Fuel Delivery (Gravity Feed to Fuel Pump)
Fuel Tank Capacity (19 L (5.0 gal.)

Drive Train Mower Deck (36-inch)

Blades (2
Blade Bolt Torque (81 N·m (60 lb-ft.)
Cutting Heights (25-114 mm (1-41/2 in.)
Weight (86.7 Kg (191 lb)
Overall Width (chute up) (927 mm (36.5 in.)

Mower Deck (48-inch)

Blades (3
Blade Bolt Torque (68 N·m (50 lb-ft.)
Cutting Heights (25-127 mm (1-5 in.)
Weight (83.6 Kg (184 lb)
Overall Width (chute up) (1308 mm (51.5 in

ower Deck (54-inch)

Blades (3
Blade Bolt Torque (68 N·m (50 lb-ft.)
Cutting Heights (25-127mm (1-5 in.)
Weight (86.7 Kg (187 lb)
Overall Width (chute up) (1460 mm (57.5 in.)

Recommended Lubricants

Engine Oil (John Deere PLUS-4
Grease (John Deere MOLY HIGH Temperature EP
Transmission Oil (HY-GARD-J20C (TURF-GARD-SAE10W-30 (PLUS-4-SAE10W-30 (TORQ-GARD SUPREME-SAE30
(Specifications and design subject to change without notice.)

start mower disconnect battery keeps running alt good if stops battery no good

do a compression test just had one with a blown right side head gasket

We had issues in the UK with issues like this, they would blacken and soot up the plugs and start to run on on cylinder, there was an internally vented carb rather than the externally vented carb to cure this.

each lever has its own safety switch one of them has failed jumper each one to test them

When you had the fuel filter off, did gas flow freely from the hose? Sounds like maybe the tank has dirt in it blocking the fuel line. Other than that, maybe there is dirt in the carburetor bowl.


http://www.mylawnmowerforum.com/forum/

Toro is a great brand, but the Home depot models are for home use. IF it won't start correctly you should troubleshoot the problem as this is a built in safey system for your benefit. There is a switch on both parking breaks, A switch to detect you sitting in the seat. The PTO must be disengaged. Check each of these. If you have your manual you can view the schematic diagram, and test each switch. If not, you can download a manual from Toro web site. According to your model and serial number your deck would only have two blades. They also have what they call "blade stiffeners" . Your results from buying power equipment from a big box store is typical. If you need service, pay a little more, and buy from your local power equipment distributor.

sounds like you need to clean out the carby and flush the fuel tank ,your problem would be caused by some dirt or something holding the float needle open.