Cool Weather Engine Starting Tips
Recommended Cold
Weather Starting for
Small Gas Engines
1. Use engine oil rated for cold temperatures.
2. Use fresh winter grade fuel (87+ Octane).
3. Spray starting uid into the carburetor.
4. Warm the engine oil.
Cold weather makes small engines dicult to start for
two reasons. First, oil thickens when it’s cold, which
makes it harder for the engine to turn over. Secondly if
the engine’s gas tank has summer blend gasoline, this will
contribute to diculty in starting in cold temperatures.
1. Use engine oil rated for
cold temperatures.
Two of the most common oils
are 5w30 and 10w30. Multi-
grade oils are designed to
perform at both cold starting
temperatures and normal
operation temperatures without
sacrificing performance. Viscosity measures a liquid’s
resistance to flow (aka its thickness). e first number
in the viscosity grade is the low temperature, winter
rating (i.e. 5w and 10w). In fact, that’s what the “w”
stands for: winter. e second number in the viscosity
grade is the high temperature rating (i.e. 30). e
viscosity is measured at 210° F to represent the normal
operating temperature of an engine.
Switch to a lighter-weight oil in the winter. SAE
5W30 is recommended for operating temperatures
below 40˚F (4˚C). Follow the engine manufacturer’s
recommendations in the engine Owner’s Manual.
2. Use fresh winter grade fuel
(87+ Octane).
ere is summer blend and
winter blend gasoline. RVP
(Reid Vapor Pressure) is the
measure of the vapor pressure,
or volatility, of gasoline at 100
degrees Fahrenheit. Refineries,
pipelines and fuel storage facilities will add butane to
gasoline to keep the RVP high enough in the winter
months so gasoline has sufficient volatility. In the
winter time approximately 10% to 12% of the makeup
of gasoline is butane. Gasoline engines need the
higher volatility to help start when it is cold. If your
equipment’s engine has summer blend gasoline in its
fuel tank, then it will contribute to difficulty in cold
weather starting.
Drain the gasoline from the engine’s tank (or run the
gasoline out if the engine will start) and replace with
fresh winter grade fuel that is 87+ Octane rated.
3. Spray starting uid into the
carburetor.
Starting fluid is a volatile,
flammable liquid which is used
to aid the starting of internal
combustion engines, especially
during cold weather or in engines
that are difficult to start using
conventional starting procedures.
Starting fluid’s main ingredient is
ether. It is highly flammable, so it should be used with
extreme care. Spray directly into carburetor, air cleaner
or air intake for a few seconds, then start engine. Do
not flood engine before using. In order to prevent a
backfire, do not start engine with the air filter off. Do
not use while the engine is running.
4. Warm the Engine Oil.
ere are several ways to warm
the engine’s oil the simplest
being to move the equipment
into a warm place overnight.
ere are pad heaters available
from auto supply stores that
attach to the engine’s oil pan
and plug into a standard 110V electrical outlet. ese
heaters slowly and uniformly heat the oil pan so the
oil becomes thinner enabling the engine to start. e
wattage of these pad heaters can vary and so will the
actual time (1 - 2 hours) that it takes to warm the oil
in the engine’s pan. Always follow the manufacturer’s
instructions for connection and safe use.
ENGINE
STARTING
FLUID