This is a verbatim copy of the email I've sent to Primus support (haven't heard from them yet), maybe someone here would be able to help?..

I’ve just bought an Omnilite TI but can’t understand how to prime it with 0.25 jets (for heavier fuels). It works perfectly with other jets. The fuel just won’t flow, even though the bottle is pressurised and the system is clean (it’s a new stove). If I put the stove to its side, I can have a few drops of kerosene, but not enough for priming. As soon as I replace the jet to 0.32, kerosene starts flowing profusely. Or, if I unscrew the 0.25 jet, the fuel is flowing through it, but not if it’s screwed down. If I pour fuel manually from a bottle, burn it and prime the stove, then 0.25 jet works perfectly with kerosene. The problem is with getting the fuel flow BEFORE the system is hot. I have even tried replacing that 0.25 jet with a new one from the service kit but it still won’t work.

To sum it up:

  • 0.36 jet with gas - OK
  • 0.32 jet with any kind of fuel - OK
  • 0.25 jet with any kind of fuel (kerosene, white gas) - fuel won’t flow for priming (20-30 pump strokes, almost full bottle). When the system is hot, fuel will vaporise and burn, but not before.

I’m testing it in perfect conditions, with no wind and on a warm sunny day.

Any ideas or advices? Am I doing something wrong?..


2 Answers 2


I've written to the Primus support and received this answer:

The 25 jet for Kerosine is more of a in emergency use part. The kerosine is harder to get to light and will be problematic and will sot a lot. it needs to be primed for a long time and it might eaven be that you need to pour some on the stove and light it to let it burn for a while to prime it. it needs to be hot and will take time, its normal for that kind of fuel.

So you are doing it right and when the stove gets going as you say it gets vaporized and burns ok.

HOWEVER, I think I've found a cause and a solution: if kerosene or other heavy fuel refuses to flow before being heated, you shall poke the jet with the nozzle-cleaning needle. Even though the jet was not dirty, maybe some scum from the fuel entered the nozzle and clogged it. It's a very thin one so it doesn't take too much to block it!

  • These heavy fuels often contain additives that are helpful in engines but not stoves, or can give a little wax, so it's not really surprising that they can block nozzles. As the stove is new, it's also possible there was a fragment of metal or even packaging caught in the nozzle.
    – Chris H
    Aug 19, 2020 at 7:37
  • 1
    Are the spelling mistakes ("sot", "eaven", "its") in the reply you received, or is that due to your transciption? Jul 9, 2023 at 11:23
  • @TobySpeight I copied their response verbatim 😁
    – Alexander
    Jul 10, 2023 at 21:25

I think 0.25mm Jet seems not to be the industrial product, and so many defective jets. The hole of 0.25mm Jet is sometimes defective, often cannot pass through the cleaning needle easily.

I use 0.32mm Gasoline Jet for Kerosene and I can confirm blue flame. So I always set 0.32mm Jet, and I use Kerosene and sometimes white gasoline.

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