John Deere Models 425, 445, F911 and 6X4 Gator Kawasaki FD620D Camshaft Replacement


Typically, the plastic camshaft gear in the Kawasaki FD620D engine will fail between 800-1200 hours.  When it does fail, the amount of engine damage may be just the plastic gear or much more. The last engine I repaired looked like a plastic hand grenade exploded inside the crankcase. I had to replace the camshaft, water pump gear, oil pump gear and the complete governor assembly.  There were plastic teeth in the oil pump and every nook and cranny inside the engine.

Steel camshafts replaced the plastic version in production models starting in February 1998 in FD620 engines so this problem does not apply to the following engines.

FD620D-CS00 – Beginning serial 153727 – John Deere Model F911
FD620D-DS02 – Beginning serial 149283 – John Deere Model 425
FD620D-CS01 – Beginning serial 150198 – John Deere Model 445
FD620D-ES11 – Beginning serial 152490 – John Deere Model 6×4 Gator

These are the Kawasaki serial numbers not the John Deere equipment serial number. The engine serial number is located in the front of the engine under the drive shaft. There was NO recall of the engines since the warranty had expired on the engines.

In general, I would rate the difficulty of this repair a 5 on a scale of 1-10. The most difficult thing is to identify the parts to be replaced. I would DEFINITELY get a copy of the Technical Manual for the engine.  There are bolt torque specifications and important information that are not included in this document.

John Deere Technical Manual TM1517 425, 445 and 455

The procedure to replace the Kawasaki FD620D camshaft can be :

Level 1 Replacing the camshaft before it fails.

Level 2 Replacing the camshaft after it fails.

A Level 1 replacement will require less material since there will be little damage to other engine components.  There are a minimum number of components that must be replaced. There are other optional steps that are not expensive which should be considered since once the engine is apart they are quite simple.

The valve springs and tappets are different for the steel camshaft, but the push rods are the same.  I would also replace the push rods since they may be worn or bent and they are not that expensive.  When a head is removed I always replace the old gasket. The FD620D engines do have a habit of blowing a head gasket on the right side. Leaking antifreeze into the crankcase is also a fairly common problem.  My personal opinion is that I will ALWAYS replace the head gaskets even for a Level 1 replacement.

I would check the compression psi of each cylinder, Level 1.0.  The pressure should be 170 or higher with no more than 14 psi difference between the cylinders. If the pressure is low, you may want to consider honing the cylinders and installing new rings.  Lapping the valves is also recommended.

The water pump is enclosed inside of the engine.  There is only one little seal to prevent the antifreeze from getting into the crankcase. A new water pump is around $70 or you can replace the internal seal and o-ring inside the pump for less than $2.  You will already have removed the water pump to remove the crankcase cover so I ALWAYS include the optional steps 1.17 and 1.18.

There are camshaft replacement kits available on the internet, but the parts list will vary and how do they know what I will need. I order the parts separately to get exactly what I need.  When you open the crankcase cover, you can begin to determine the necessary parts.

I only want to see the inside of the crankcase one time. Do not be penny wise and dollar foolish. (Just my opinion)

The Level 1 repair steps are 1.1 to 1.16.

1.0 Test each cylinder’s compression.

1.1  Replace the camshaft.

1.2  Replace four tappets

1.3  Replace four valve springs

1.4  Replace the water pump case seal

1.5  Replace the water pump seal.

1.6 Replace oil pump gasket

1.7 Replace oil pump O-ring

1.8 Replace crankshaft seal

1.9 Replace crankcase cover gasket

1.10 Remove the oil sump plate and clean.

1.11 Remove the oil screen, inspect and clean.

1.12 Replace the exhaust/muffler gaskets.

1.13 Replace the intake manifold gasket

1.14 Replace the intake manifold gasket

1.15 Replace the oil filter and add new oil.

1.16 Replace the antifreeze.

1.17 Run the engine for 30 minutes.  Adjust the valves and torque head bolts.

I included a column in the parts table titled Part Location. This shows the John Deere Parts Catalog 2351 page locations for 425, 445 and 455 Lawn and Garden Tractors Sectional Index 20 (425/445 Gas Engines).  The location 20-4-(7) indicates the part can be found in Section 20, Page 4, and the item number (7) is in parenthesis. You can start an account to look up and price parts.

Level 1 Parts Table







Part Description Part   Cost






Steel   Camshaft $165 20-4-(3B)




Tappet $37.40 20-4-(7)




Valve   Spring $9.12 20-4-(11)




Gasket,   Water Pump Case $6.83 20-6-(26)




Gasket,   Water Pump Cover $4.93 20-6-(37)




Gasket   Oil Pump $.83 20-2-(36)




O-Ring   Oil Pump $.77 20-2-(37)




Crankshaft   Seal $4.90 20-2-(20)




Gasket,   Crankcase Cover $18.15 20-2-(23)




Clean   oil sump 0 20-5-(6)




Clean   oil screen 0 20-5-(5)




Gasket,   Exhaust/Muffler $7.94 30-25-(2)




Gasket,   Intake Manifold $2.35




Gasket,   Intake Manifold $2.35




Oil   Filterand   new oil $7.68 20-5-(1)




Antifreeze *


Run   engine adjust valves


Check   torque the head bolts
Total   Cost $268.25

Level 1 Optional Steps

The Level 1 Optional Steps are a good idea since the gaskets and seals deteriorate over time. The engine crankcase is open and steps 1.17 and 1.18 will cost less than $15. Valve cover gaskets can be easily replace with the engine in the tractor.

The water pump and oil pump gears are PLASTIC. They should be closely inspected for cracked or missing teeth. These are less than $10 and would require

1.18 Replace Valve Cover Gaskets

1.19 Replace Head Gaskets

1.20 Replace Water Pump Seal

1.21 Replace Water Pump Gasket

1.22 Replace the Water Pump Spur Gear

1.23 Replace the Oil Pump Spur Gear

Level 1 Optional Parts Table

Level   Number Qty. Part   Number Part Description PartsCost



1.15 2 MIU11358 Gasket,   Valve Cover $12.66


1.16 2 M97309 Gasket,   Cylinder Head $32.46


1.17 1 M76118 Seal,Water   Pump $4.05


1.18 1 M176145 O-ring,   Water Pump $.95


1.19 1 M76098 Spur   Gear, Oil Pump $5.23


1.20 1 M76144 Spur   Gear, Water Pump $3.80


      Total   Cost $53.92

These prices are list prices from my local John Deere dealer. I would give your dealer this parts list and ask for a quote.  My dealer took off about 10%.<
My recommendation is to perform steps 1.0 to 1.20 which will cost $318.80

John Deere does have a MIA10941 Kit, Engine Gasket, for $143.77 that includes all of the gaskets, oil screen and a few washers.

Level 2 Optional Steps
This will include all of the Level 1 steps and will depend on the degree of damage to the engine components.  This is a list of problems I encountered on my last engine rebuild.

Some of these steps will not be optional.  When I disassembled my FD620D,

the cam gear looked like it had been wobbling and broke teeth all around the plastic gear. The governor was totally destroyed, the oil pump spur gear had a broken tooth and the water pump spur gear had a crack.  You will need to carefully inspect each component for damage.

Since I had removed the heads, I thought I might as well check the pistons and cylinders.  I removed the pistons to find one had stuck compression rings. I de-glazed/honed the cylinders and bought new rings.  I had a machine shop check the cylinders to be sure they were OK.

2.1 Replace the governor gear assembly.

2.2 Replace the replace the governor Arm.

2.3 Replace the governor sleeve.

2.4 Replace governor arm seal.

2.5 Replace the flywheel end crankshaft seal.

2.6 Clean and lapp the valves.

2.7 Clean water jackets around the cylinders.

Level 2 Parts Table


Level   Number Qty. Part   Number Part   Description Part   Cost



2.1 1 AM105569 Governor   Gear Assy. $7.65 30-32-(16)
2.2 1 M76155 Governor   Arm $5.73 30-32-(9)
2.3 1 PT9996 Governor   Sleeve $4.90 30-32-(14)
2.4 1 M88987 Seal,   Governor 20-2-(29)
2.5 1 M76145 Seal,   Crankshaft $4.90 20-2-(20)

Tools needed.

 Level 1

Cylinder Compression Gauge

Spring Compressor

 Level 2

Ring Compressor

Harmonic Balancer Removal Tool


Article provided by Bouford Buckets.





  1. Scott says:


    First, I appreciate finding a comprehensive listing of all parts and info regarding this problem! I’m in the middle of doing this repair for my sister/brother inlaw’s 425 and I have a couple questions for you.

    You note above that the replacement camshaft has different tappets and springs that are needed, I was unaware of this… I’m about to order parts and want to make sure I have everything on hand and that I need.

    I tore it apart today and the camshaft is wasted but I see no other apparent damage. There is a slight blemish/chip on the drive gear for water pump but other than that I see no other damage. I might add, the mower wouldn’t start the beginning of this mowing season so I think they were lucky in that the cam gear teeth were damaged while trying to start for first mow, not while running.

    So, my questions…

    1) Do I really have to replace tappets/springs/push rods during installation of new steel cam gear? If not, can it be done w/o removing heads? I had thought possibly I could put it together w/o removing them but maybe have to loosen rocker arms. Having said this, when I removed cam shaft I did match up timing marks in order to slide shaft out, then it rained down rods and tappets. Not sure if its possible to put it back w/o removing heads… any clarification on this would be awesome!

    2) Since there is no apparent damage is there any reason to replace additional gears, ie: oil pump, governor, water pump?

    I have found 2 different replacement kits, the first one includes:

    Steel Camshaft
    Aluminum Oil Pump Gear
    End Cover gasket
    Both Water Pump Gaskets
    2 Exhaust Gaskets
    Governor Gear
    Governor Tip
    Oil Filter
    2 Sparkplugs
    2 Valve Cover gaskets
    Oil Pump O-Rings.

    $239 on ebay –

    The second one includes:

    (1) Steel gear cam (replacing earlier plastic one)
    (1) oil filter
    (1) crank cover gasket
    (2) head gaskets
    (1) governor assembly
    (4) valve springs
    (4) tappets
    (4) push rods
    (2) rocker case gaskets
    (1) pivot arm
    (1) oil seal
    (1) intake/manifold gasket
    (1) intake gasket
    (1) pump gasket
    (1) pump gasket
    (2) exhaust/muffler gasket
    (1) sleeve
    (1) oval o-ring.

    $259 on ebay –

    I know this being a holiday weekend I will be lucky if you reply back very quickly, but would love your input asap as I want to get the right parts order and some answers to my questions.

    Feel free to email me directly and/or maybe we could even have a phone conversation. I was an auto mechanic for 7 yrs but new to small engine repair. I had been told by someone that this repair shouldn’t be thought of like a car with similar problems. Directly meaning that I wouldn’t have to replace a bunch of parts that weren’t needed. I just need some clarification from someone that “knows”.

    Thank you and I look forward to your reply.

  2. […] Check the compression properly. If you have ~170 PSI on each cylinder you can eliminate mechanical (piston, rings, cylinders head gaskets, valves and cam) problems. Here's more information that may help: John Deere Models 425, 445, F911 and 6X4 Gator Kawasaki FD620D Camshaft Replacement :: John Deere Te… […]

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