Kawasaki FD661D

Kawasaki FD661DThe Kawasaki FD661D is a 0.62 l (617 cc, 37.65 cu-in) V-twin 90° liquid-cooled 4-stroke internal combustion small gasoline motor with horisontal shaft, manufactured by Kawasaki Heavy Industries LTd., for general-purpose applications.

The FD661D has OHV (overhead valve design); cast-iron cylinder liners; float type carburetor with fixed main jet; transistorized fuel pump; full transistor ignition system with fixed timing; mechanical governor and low tone muffler. The Kawasaki FD661D uses a full pressure lubrication system with spin-on oil filter and dual element air cleaner.

The engine was equipped with solenoid shift-type electric starter and 12V-20A charging coil with a regulator.

The Kawasaki FD661D develops 22.3 PS (16.4 kW; 22.0 HP) at 3,600 rpm and 45.7 Nm (4.66 kg·m; 33.73 ft·lb) at 2,400 rpm of torque. It has a 76.0 mm (2.99 in) cylinder bore and 68.0 mm (2.68 in) piston stroke. Compression ratio rating is 10.3:1.

General information

Engine Specifications
Type4-stroke, OHV, V-twin 90°
Displacement617 cm 3 (37.65 cu-in)
Max. horsepower22.3 PS (16.4 KW; 22.0 HP) at 3,600 rpm
Max. torque (crank PTO)45.7 Nm (4.66 kg·m; 33.73 ft·lb) at 2,800 rpm
CarburetorFloat type
Cooling systemLiquid-cooling
Ignition systemTransistorized ignition
Lubricating systemPressure feed lubrication system
Starting systemElectric starter
Charging system12 Volt – 20A with regulator
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel consumption230 g/HPh
Cooling systemPressurized forced circulation type

Dimensions and Weight

Kawasaki FD661D
Length, mm (in)556 (21.9)
Width, mm (in)437 (17.2)
Height, mm (in)586 (23.0)
Dry weight, kg (lb)47.2 (104.1)

Cylinder Block and Head

Cylinder block
Compression ratio:9.0:1
Bore x stroke:76.0 x 68.0 mm (2.99 x 2.68 in)
Cylinder internal diameter (standard):76.067 mm (2.9948 in)
Piston skirt outer diameter (standard):75.875 mm (2.9872 in)
Number of piston rings (compression / oil):2/1
Connecting rod small end diameter (standard):17.051 mm (0.6713 in)
Piston pin diameter:16.975 mm (0.6683 in)
Side clearance:Top0.150 mm (0.0059 in)
Second0.120 mm (0.0047 in)
Ring end gap:Top1.200 mm (0.0472 in)
Second1.200 mm (0.0472 in)
Ring width:Top1.120 mm (0.0441 in)
Second1.120 mm (0.0441 in)
Oil1.500 mm (0.0591 in)
Cylinder head
Valve arrangement:OHV
Valves:2,(4 valves in total)
Valve steam diameter:INTAKE5.945 mm (0.2341 in)
EXHAUST5.925 mm (0.2333 in)
Valve spring free length:INTAKE29.70 mm (1.1693 in)
EXHAUST29.70 mm (1.1693 in)

Tightening torque specs

Tightening torque specs
Cylinder head21 Nm; 2.1 kg·m; 15.5 ft·lb
Connecting rod21 Nm; 2.1 kg·m; 15.5 ft·lb
Flywheel110 Nm; 11.2 kg·m; 81 ft·lb
Crankcase cover25 Nm; 2.5 kg·m; 18.4 ft·lb
Intake manifold8 Nm; 8.0 kg·m; 6 ft·lb
Oil drain plug23 Nm; 2.3 kg·m; 17 ft·lb
Valve clearance lock nut8.8 Nm; 0.9 kg·m; 6.5 ft·lb

Maintenance data

Maximum speed3500 ± 100 rpm
Idle speed1500 ± 100 rpm
Cylinder compression12.0 kg/cm2 (170 psi) at 500 rpm
Valve clearance
Intake valve0.25 mm (0.010 in)
Exhaust valve0.25 mm (0.010 in)
Oil system
Oil type4-stroke or an equivalent (SC, SD, SE, SF, SG, or SH)
Recommended oilSAE 10W-40, 10W-30, 5W-20
Oil capacity (with filter changed)1.5 L (1.6 US qt)
Ignition system
Spark plugNGK: BPR5ES
Spark plug gap0.6-0.7 mm (0.024-0.028 in)
Spark plug tightening torque15 Nm; 1.5 kg·m; 11 ft·lb
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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  1. What is the most common cause of the engine surging and running ruff once it’s warmed up

  2. Looking for wiring diagram for this engine FD661D, in particular, the voltage regulator. Original connector is falling apart. 6 pins.

      • If you haven’t found one yet go to Ventrac website and look for Manuel’s then go to the 4000 model tractor (it has been discontinued) and download the Manuel the Kawasaki FD661D wiring diagram will be one of the first things in that Manuel.

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