Maintenance and Trouble Shooting

OmniFuel, OmniLite Ti and Multifuel EX Stoves (plus stoves with generator: all Gravity-models, Eta Spider, Eta Power, Express Spider, Varifuel and old MultiFuel)

Before using your stove for the first time, you must read the manual carefully. Study these instructions at regular intervals to remain familiar with the operation of the appliance and keep them for future reference. Failure to follow these instructions may result in serious injury or death!

How to do maintenance on your multifuel stove

A muitfuel stove needs regular maintenance and a good idea is to look after it both before and after your outings. To make the maintenance easier, even when out on the field, our multifuel stoves are built with very few parts that are all easy to replace.


If you discover that your stove isn't functioning as normal, or if you notice that the fuel supply doesn't feed the burner properly here is a video on how to best troubleshoot the stove.


“Jet test”

If your stove starts "coughing“ or burning unclean, it usually results from debris in the jet or
fuel line to the jet.
 Perform the following steps to clean the system.


Unscrew the jet and check against a source of light that you see the hole. If not clean with cleaning needle (alternatively, use compressed air). On this occasion, make sure to mount the correct jet for the fuel you use:

OmniFuel: Cartridge Gas 0.45 mm, White Gas (or leaded) 0.37 mm, Paraffin/Kerosene or Diesel 0.25 mm
.

OmniLite Ti: Cartridge Gas 0.36 mm, White Gas (or leaded) 0.32 mm, Paraffin/Kerosene or Diesel 0.25 MultiFuel EX: Cartridge Gas 0.37 mm, White Gas (or leaded) 0.32 mm, Paraffin/Kerosene or Diesel 0.28 mm.

Check fuel supply

Attach the fuel bottle, open the shut-off valve on the fuel line (on OmniFuel and OmniLite Ti also the gas control valve on the stove) and check whether fuel flows out of the jet bore (with jet NOT mounted). If there is no
or poor flow, proceed with a pump check (see instruction below).

Mount the jet

(you may tighten it quite hard, in particular if a small flame at the jet occurs it shall be tightened
harder) and the flame spreader again.

OmniLite Ti and Omnifuel: First open the shut-off valve on the fuel line and then the control valve on the.

Mulitfuel EX: only open the shut-off valve on the fuel line. Now a hearty beam of fuel towards the flame spreader shall occur. Let it spray for 2 seconds with white gas or 2-5 seconds with kerosene/paraffin or diesel. Note: on Mulitfuel EX there will be a slight delay between closing the shut-off and the stop of the fuel flow.

Pre-heating

Lighten the fuel carefully (watch out for flame shots when using white gas) and let it burn for until you hear a hissing sound. With white gas this will take 1 minute max. It might take slightly longer when using kerosene / paraffin or diesel.


If you have cleaned the jet but the stove works only for a few times, there is more debris somewhere in the system. Take apart the entire system and clean it – ideally with compressed air. This entire procedure must be performed more frequently when using kerosene / paraffin or diesel often (due to the soot that these fuels produce).

Addition between point 3. and 4: for all Primus stoves with generator (all Gravity-models, Eta Spider, Eta Power, Express Spider, Varifuel and MultiFuel)

All these stoves have a generator (a brass tube that leads through the flame). During the gasification process debris might occur. To get rid of them, tear out the stele wire from the generator with a plier or the tool and clean it carefully. Blow through the generator with compressed air and mount everything.

Checking the Pump

Maintenance leather gasket

If you pump to create pressure in the fuel bottle, you must feel some friction and resistance and hear a pumping sound (just like on a bicycle tire). If the pump feels limp the leather gasket must be stretched and lubricated. Unscrew and withdraw the pump rod. Rub oil or grease into the gasket until it becomes soft and pliable. The Primus silicone grease is best, any other will do as well. If the pump still fails to pressurise the fuel bottle, replace the gasket.

Non-return Valve

If the pump seems to work but the bottle fails to maintain the pressure in the fuel bottle, check and clean the non-return valve. Unscrew the plastic screw at the bottom of the pump take out the spring (is it still ok?) and the brass cone (don’t loose the small pieces). Take out the rubber gasket (O-ring) from the pump, check it, clean with a cloth and refit or replace it.

Stove doesn’t stop burning

In order to put out the stove turn fuel bottle in such a way that on the pump the label "OFF" points upwards. After maximum 1 minute the stove should die down and only compressed air comes from the bottle. If the stove keeps on burning, there is a problem. Check that the brass fuel intake pipe of the pump is OK (on older pumps it may be plastic). Is the pipe properly connected to the pump head and is it mounted in the correct angle? Adjust if necessary.

MultiFuel EX only

The pump is OK but there is still no flow of fuel. Unscrew the fuel line from the stove and check whether fuel flows from the line now. If this happens but not on the jet, you have to replace the fuel filter. It is mounted right where the fuel line is attached on the stove. If compressed air is available blow through the entire system. If the filter is clogged during a trip, you can use your stove without the filter until you get a replacement filter.

General Advice

To turn off the stove, turn the fuel bottle in such a way that on the pump the label "OFF" points upwards. Then, only compressed air flows through the entire system after a while and cleans it from the inside. If fuel leftovers remain in the system, it can easily clog, particularly if you frequently burn paraffin/kerosene or diesel. We generally recommend to use cartridge gas (Primus LPG gas) or as liquid fuel white gas (Primus Powerfuel or similar). These fuels have the relatively highest energy content, burn very cleanly and require least cleansing and maintenance.

Multifuel Kits

Primus