A Look at Snowmobile Exhaust
Power Valves
Mounted in the exhaust port of certain
snowmobile models, exhaust power valves are devices designed
to improve combustion efficiency at varying RPM. Improved
efficiency increases horsepower and lowers exhaust emissions.
At low RPM the valves are in
a closed position, allowing for more efficient combustion
and minimizing the levels of unburned gases escaping down
the exhaust port. At high RPM the valves are in an open position,
allowing the motor to breathe more freely and improving the
scavenging effect needed for efficient performance in two-cycle
motors.
Because exhaust power valves
are located in the direct stream of exhaust flow, deposits
consisting of soot, carbon and ash quickly accumulate, requiring
the valves to be cleaned regularly. If they are not cleaned,
they may get stuck, and operators will notice a considerable
power loss and/or bog-type operation.
Exhaust
power valve with deposit build-up
Clean exhaust
power valve
In some instances, deposit build-up
may be worse than others. There are several reasons for this:
The machine may be consuming
more oil than is needed. Oil injection pumps vary the amount
of oil injected based on the throttle position. As the throttle
is opened, oil consumption increases. AMSOIL 2-Cycle Oils
are recommended for use at 50:1 mix ratios, but if the sled
is consuming more than one quart of oil per 12 gallons of
gas, it is exceeding an average mix ratio of 50:1. The less
oil the sled burns, the fewer the deposits that accumulate
on the exhaust power valves. If you wish to have a sled’s
oil injection pump setting checked, AMSOIL recommends bringing
it to a local dealership so a qualified snowmobile mechanic
can make the correct adjustments.
Another contributing factor
to excessive deposit build-up is riding style. Snowmobiles
operated at low speeds and/or steady RPM for extended periods
of time will accumulate deposits more quickly than snowmobiles
operated at higher speeds. Two-cycle motors do not operate
at maximum efficiency at slower speeds, causing a large percentage
of unburned fuel and oil to exit through the exhaust. This
unburned material accumulates on exhaust valves and forms
deposits. Also, since snowmobiles operated at low-level constant
RPM do not frequently actuate the valve, it allows deposits
to form more rapidly, requiring more frequent valve maintenance.
Snowmobiles run at higher RPM
operate more efficiently and can extend time between valve
cleanings. Efficient operation results in increased combustion
temperatures and more complete burning of the oil/fuel charge.
Higher RPM also means the exhaust power valve is more frequently
actuated, disrupting deposits and slowing down their accumulation.
Finally, the type of two-cycle
oil used in a snowmobile can improve valve cleanliness and
extend maintenance. Because they effectively fight deposit
formation, AMSOIL Synthetic 2-Cycle Oils exhibit better overall
performance than petroleum two-cycle oils. AMSOIL Synthetic
2-Cycle Oils also resist friction and heat more effectively,
burn cleaner and can safely be used at 50:1 mix ratios.
Routine maintenance is important
for snowmobiles equipped with exhaust power valves. However,
maintenance can be eased through the following:
New AMSOIL 2-Cycle Oils provide second-to-none protection
and performance in modern two-cycle equipment
Two-cycle engines remain the
workhorses in recreational equipment, including outboard motors,
motorcycles, snowmobiles and personal watercraft, as well
as in lawn and garden applications like lawn mowers and weed
eaters. Design changes over recent years have included direct
fuel injection engines, in which fuel is injected directly
into the combustion chamber, and exhaust power valves, which
improve combustion efficiency at varying RPM. These design
changes have allowed two-cycle engine manufacturers to effectively
reduce emissions, improve fuel efficiency and decrease oil
consumption. Today's two-cycle motors of all types require
specialized oil technology to deliver maximum engine protection,
dependable operation and long service life.
As the leader in two-cycle oil
technology, AMSOIL has performed extensive research in developing
a new line of revolutionary, specialized oils called the "Fabulous
Four." AMSOIL INTERCEPTOR Synthetic 2-Cycle Oil (AIT)
was the first new oil to be introduced. It is primarily recommended
as an injector oil or at a 50:1 mix ratio in carbureted, electronic
fuel injected (EFI) and direct fuel injected (DFI) snowmobiles,
personal watercraft, motorcycles and ATV's. Formulated with
wax-free premium quality synthetic esters and a specialized
additive package, INTERCEPTOR is designed to address the exhaust
valve sticking problems associated with certain snowmobile
models.
New AMSOIL HP Injector Synthetic
2-Cycle Oil (HPI),
DOMINATOR Synthetic 2-Cycle Racing Oil (TDR)
and Saber Professional (ATP)
and Outboard (ATO)
Synthetic 100:1 Pre-Mix 2-Cycle Oils complete the Fabulous
Four lineup, replacing AMSOIL Synthetic 2-Cycle Injector Oil,
Series 2000 Synthetic 2-Cycle Racing Oil and 100:1 Pre-Mix
Synthetic 2-Cycle Oil, respectively. The application chart
below ranks each oil's performance in common two-cycle applications.
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work with you personally as your servicing AMSOIL Dealer.
Use the information on this website to contact me. You may
also check out the AMSOIL
Corporate Website for product and business opportunity
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