additives which will contaminate your stove and are hazardous for your health. If you
have to use automotive gasoline, use unleaded gasoline wherever possible. Gasoline
is highly flammable and preheating occurs quickly. However, gasoline is also very
volatile and burns explosively.
KEROSENE -
Kerosene has more or less the same energy value as gasoline but is
considerably less of a hazard in terms of fire. It is used all over the world and is easy to
get hold of. You can often find kerosene in
places where you would not find other fuels, such as in food stores. Preheating takes
slightly longer with kerosene than with gasoline and is slightly sooty, but there is not
much of a risk of explosion. Kerosene also requires you to clean the burner more often.
We recommend the use of kerosene, as it is primarily designed for use in stoves and
heaters. We do NOT advise the use of lamp oil or fire lighting fluid (charcoal lighter).
NOTE: In harsh cold, there is a risk of kerosene solidifying, which makes the stove
unusable.
DIESEL -
Diesel is somewhat similar to kerosene, but preheating takes slightly longer
and it produces even more soot. We recommend that you only use diesel as last
option. If you do so, use diesel for cars. Avoid marine diesel entirely. One positive
aspect of diesel is that it can be found all over the world.
FUEL CONSUMPTION -
Expect to use 0.10-0.15 liters (3.3 – 5 fl. oz.) of fuel per
person per day. In the winter, you will use more fuel for melting snow, preheating for
longer, etc. In this instance, expect to use twice as much fuel. To keep your fuel
consumption down, it is important to adjust the flame so that the stove burns as
efficiently as possible. This does not mean opening the control valve as much as
possible; quite the opposite, in fact. If you do that, you will use up more fuel but your
food will not cook any faster. To heat your food as quickly as possible, it is also a good
idea to always use a lid on your pan and make sure that the pan is protected from the
wind.
Visit www.optimus.se for more information about fuels.
TIPS
CHOOSING A FUEL
Liquid fuels work considerably more effectively than gas in cold conditions. The
pressure in gas tubes is impaired at just a few degrees below freezing. Keep in mind
that some poor qualities of kerosene and diesel will solidify in the cold. If you are not
sure what will happen, you can place a bottle with the fuel in your freezer and see what
happens.
PARTS SUSCEPTIBLE TO COLD
The quick connect and O-rings are the stove parts most susceptible to cold. The O-
rings may stiffen and crack when the temperature falls below -20 °C (-4 °F). Check
them before leaving on your trip, and replace them if they look worn.
EFFICIENT FOOD PREPARATION
When the weather is cold, it is of course even more important to use a wind screen and
a lid on your pan when cooking: this considerably reduces the amount of time/fuel
needed to heat your food.
TMFB ON SNOW
When you use your TMFB on snow, it is important that you place a non-flammable
base beneath the stove so that it will not sink into the snow while you cook. Set up a
surface on which you can place the stove, bottle and pans, and pack the snow down
hard so as to form a firm base.
MELTING SNOW
You can melt snow more quickly if you start with a little water in the bottom of the pan.
It takes longer to melt ice than it does to melt snow.
WASHING DISHES IN WINTER
Washing up pans is always a little more complicated in the winter. Use Teflon coated
pans and leave the leftover food to freeze before scraping it out with snow. You can
also dissolve grease in the pans using cooking oil and then wiping it out. It is a good
idea to boil water for dishwashing right after cooking in order to save fuel.
TMFB AT ALTITUDE (MORE THAN 4,000 METERS)
The TMFB is one of the best stoves on the market for use in extreme situations.
Among other things, this stove has been used successfully in the Himalayas at
altitudes of 7,400 meters. However, using multifuel stoves with liquid fuels at altitudes
in excess of 4,000 meters can cause problems. Burning may be uneven due to the fact
that there is less oxygen in the atmosphere. Choose your fuel carefully and make sure
that there is free access to air around the stove.
TROUBLESHOOTING
FUEL IS LEAKING OUT
• Between the bottle and the pump
Check that the pump is screwed on securely.
Check the rubber gasket, and replace it if it is damaged.
• At the quick connect
Check the o-ring on the tip of the fuel hose and replace it if it is damaged, worn or
missing.
• At the control valve
Unscrew the control and check the O-rings. Replace these if they are damaged.
• Between the fuel hose and the control
Dismantle, clean and reassemble.
• From the hole where the pump rod enters the pump
The pump’s drain valve is leaking and has to be replaced. This is also evident by the pump rod
slowly coming out of the pump pipe.
THE FLAME IS YELLOW AND FLARING
• Insufficient preheating
Repeat the entire preheating process, or close the control and wait a while before switching it
back on.
• You have turned the control valve too far
Turn the control valve back.
• Impure fuel
Use only petroleum based fuels such as gasoline, kerosene and diesel. Do not mix different
types of fuel.
• Poor oxygen supply
Make sure that your stove has free access to air.
• The nozzle is loose
Leave the stove to cool, then screw the nozzle into position.
THE STOVE IS NOT VERY HOT
• Bottle pressure too low
Pump a few times in order to increase the pressure in the bottle. If this does not help, check
whether the pump leather is dry or damaged. Soften it with your fingers, and lubricate it with oil or
replace it if so required. Check also that the pump is screwed together properly.
• Nozzle blocked
Clear the nozzle by moving the multitool magnets beneath the burner. If this does not help, you
will have to remove the nozzle and push the clearing needle through the nozzle hole from the
inside.
• Fuel filter clogged
Replace the fuel filter. See maintenance for details.
• Fuel grooves on the spindle blocked
Unscrew the spindle and clean the grooves.
MAINTENANCE & SERVICE
CLEARING THE NOZZLE
You should clear the nozzle in the burner every time you use the stove. This is done by moving
the multitool magnets back and forth a few times beneath the burner’s base nut. The patented
Optimus clearing needle will then be activated.
CHECKING THE O-RINGS
It is important to ensure that the spindle’s O-rings are complete and undamaged in order to avoid
fuel leakage. Get into the habit of occasionally checking the two O-rings by unscrewing the
control valve and spindle. Replace the O-rings if you suspect that they are cracked or otherwise
damaged. The tip of the fuel hose has an o-ring which may benefit from lubrication so they
function satisfactorily in cold climates. Use Optimus lubricant or another oil which can withstand
harsh cold. If you are out in winter, you must pay particular attention to all rubber O-rings and
seals. These may become hard and brittle in severe cold, and possibly crack. To be on the safe
side, replace the old ones and take a few spares with you if you are going to be out for a long
time, a long way from civilization.
LUBRICATING THE PUMP LEATHER
You should lubricate the pump leather using Optimus lubricant so the pump will function
perfectly. It is particularly important to check this if the stove has not been used for a long time.
The pump leather is located at the far end of the pump rod. This is accessed by unscrewing the
pump rod and pulling out the pump rod entirely from the pipe. Lubricate the leather using a small
amount of lubricant (butter can be used in an emergency). Be careful when replacing the pump
rod.
CLEANING THE NOZZLE AND CLEARING NEEDLE
If the stove is not functioning satisfactorily and the routine measures above do not help, the
nozzle and clearing needle may need to be cleaned. Remove the burner plate, use the tip of the
multitool as a screwdriver and unscrew the nozzle. Remove the clearing needle from the burner.
Wipe clean the clearing needle body and the inside of the nozzle. Clean the nozzle hole by care-
fully pushing the clearing needle through the nozzle.
CLEANING THE SPINDLE’S FUEL GROOVES
If the stove is still not getting very hot even though you have cleaned the nozzle and clearing
needle, the spindle’s fuel grooves may need to be cleaned. Unscrew the control valve (+) as far
as it will go. Use the multitool to unscrew the spindle nut. Unscrew the control valve fully and then
pull it out together with the spindle. Clean carefully the three grooves running longitudinally, with
the spindle on the tip, using a fingernail, for example. Take care not to damage the spindle
threads.
REPLACING THE FUEL FILTER
If you are still having problems with the stove, the fuel filter may need to be replaced. The fuel
filter is located at the end of the plastic tube on the fuel pump. Unscrew the patterned part of the
filter holder and push the filter out using a pointed object. Make sure the filter holder is clean
before inserting the new filter. If you have problems with the fuel filter, you can use the stove
without one for a brief period. It will be more sooty than usual. Some fuels also tend to flare more
if no filter is fitted. Replace the filter when you get home.
We recommend that you perform regular maintenance in order to enhance the life and
reliability of the stove. For this purpose, Optimus provides a Regular Maintenance Kit
ITEM NO. 8520. If you are going off on longer trips, we recommend that you take along
Extensive Repair Kit ITEM NO. 8510 for your TMFB stove. This will allow you to perform
advanced maintenance measures in the field.
