Buyer's Guides: Engines
Selecting a Replacement Engine
NorthernTool can match 95% of small engines correctly by simply knowing the horsepower and drive shaft information: diameter, length and type of shaft (e.g., 5/8in. x 2 7/16in. Threaded).
Horizontal Engine shaft
A Horizontal engine has the drive shaft on one side and is commonly used for water pumps, generators, Go-Karts, tillers and other general-purpose applications.
Vertical Engine shaft
A Vertical engine's shaft protrudes from the bottom, ideal for propelling the cutting blades on walk-behind and riding lawn mowers.
Finding Your Mower's Model Number
You can try getting the model number from the information plate on the old engine, then ask us to match that model number. That may not be possible, since model numbers change when manufacturers adapt engine specifications to meet new requirements from the EPA (Environmental Protection Agency) for most types of small engines.
What to Look For
Note the horsepower of the engine you are replacing. If you do not know the horsepower exactly, that's OK since most engines within a power range have a similar pattern for the bolts that mount the engine. For example, most 3 to 5 HP engines have the same bolt pattern.
Consider how you will be using the engine. For a homeowner application, for example, a standard engine will work great and will have a long, useful life. If the new engine will be used in an industrial or commercial application, we recommend you step up to an I/C (Industrial/Commercial) or other engine with cast iron cylinder sleeves to withstand the wear and tear of prolonged use.
Another consideration is the size of the engine compartment. Sometimes with a model change, the manufacturer will reposition the gas tank or adjust some other feature that may affect its compatibility with your equipment. This is rarely a problem unless you are moving up to a larger engine for more power.
View our engine comparison spec chart for model numbers, horsepower, shaft dimensions and other engine features.
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Features to Consider when Purchasing a Replacement Engine
Recoil (or rewind) starting system is operated by pulling a rope. A strong tug spins the flywheel fast enough to generate the voltage necessary for ignition.
Electronic starting system relies on battery power and a starter motor to ignite the combustion process that starts the engine. Some electric start engines have recoil backup in the event of battery failure.
OHV (Overhead Valves) engines have the valves installed in the cylinder head so they face the piston and offer greater efficiency. A more symmetrical combustion chamber means more efficient burning of the air/fuel mixture.
V-Twin Design has 2 OHV cylinders operating in the combustion chamber, considerably reducing vibration. Crankshaft size is very important to know when replacing an engine. You want to match the existing engine's shaft size with that of the the new engine to ensure a proper fit and top performance.
Gear ratio takes into consideration the equipment's application and the speed of the engine. On most small engines, the crankshaft will make 3600 revolutions per minute (RPM). In some applications — cement mixers, for example — this speed would be too high. If the engine's speed were reduced to keep the cement in the mixer, the engine would have to run at almost idle, thereby not taking advantage of the torque produced at top no-load speed (3600 RPM). Engines with a 6:1 gear ratio have a gear box that is integrated with the engine's crankshaft, allowing the engine to run at top no-load speed and still utilize the full torque of the engine. Thus, for every 6 turns of the crankshaft, the gear box and the gear boxes' shaft would turn 1 time for a final output of 600 RPM.
Low-Oil Level system causes the ignition to ground, stopping the engine (or preventing it from starting) in the event insufficient oil is in the crankcase.
Mechanical governor uses gears and flyweights inside the crankcase to sense speed and detect changes in the load, adjusting the throttle to compensate.
Pneumatic governor uses an air vane as a speed-sensing device. This air vane registers the change in air pressure around the spinning flywheel. Not as reliable as a mechanical governor.
Cast iron cylinder sleeve, piston and related components withstand wear while providing improved oil consumption for extended engine life. Because of their durability, cast iron cylinder sleeve engines are a good choice for professional or commercial applications.
Splash lubrication system directs oil to moving parts
by a splashing motion. For example, oil is splashed to bearing surfaces
with a dipper or slinger. A dipper is attached to the connecting rod that
splashes oil from the oil reservoir as the piston travels up and down
in the cylinder. A dipper can be used on both horizontal and vertical
engines. The slinger, used on vertical crankshaft engines, consists of
a spinning gear with paddles and is driven with the crank gear or cam
gear. As the slinger gear spins, oil is discharged by the paddles and
splashed throughout the crankcase.
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Generators
Why Buy NorthStar?... click here for more information
Computer Tested
All NorthStar™ Generators are factory tested to ensure reliable,
dependable, and safe operation in the field. The testing is completed
by use of automated computerized machinery that checks a minimum of 33
functions. Engine speed is checked three times. All receptacles are checked
for correct wiring.
Long Extend Run Times
All extend run NorthStar™ generators have an extra large fuel tank
which provide 8 hour run times at ½ load. This feature provides
the homeowner peace of mind by not having to get up and refuel the generator
during the night. Secondly, the extra large tank allows the construction
worker the luxury of not having to worry about refueling the jobsite generator
every couple of hours. All NorthStar™ fuel tanks have an oversized
fill neck to reduce the chance of a refueling spills. All NorthStar™
tanks have an extra drain valve to facilitate drainage of fuel from the
tank for long term storage of the generator.
UL Approved Components
All NorthStar™ generators use Underwriter Laboratory (UL) approved
components, receptacles, and lead wires. This insures a high level of
safety and quality.
Low THD
All NorthStar™ generators have a Total Harmonic Distortion (THD)
value less than 6%. Current electronic devices are more sensitive than
ever to poor electricity.
High Quality Generator Head
All NorthStar™ generator heads are of the highest quality. The electrical
windings are 100% copper. All copper windings are impregnated with a tropicalized
epoxy resin to provide insulation and protection of the wires while the
generator is operating. All insulation is NEMA Class H which provides
superior protection from heat. Heat is a byproduct from the production
of electricity.
Superior Overload Protection
All NorthStar™ generator heads can handle a 10% overload for 1 hour
every 3 hours.
Premium Engines
All Professional Portable Generators (PPG) use only premium engines such
as Honda, Vanguard, and Kohler. Premium engines have cast iron cylinder
sleeves, low oil shutdown, superior mufflers, and high quality components
used in their construction.