A Dragon with Ignition abilities

Question

I'm in the process of creating a plausible fire-breathing dragon, halfway through. As I don't want my dragon to have to eat stones to spit fire or light sparks because that could limit the dragon to certain regions, but as it will be used as a mount, this is impractical, I have made it have glands that allow it to produce a flammable oil from the fat of the animals it eats. Initially I thought of the dragon heating the oil so much that it would self-ignite when it was expelled, but the temperature needed for an oil to self-ignite varies, but is usually around 200º C. I thought the dragon could raise the oil's temperature through blood circulation around the oil bags that could accelerate until the oil is hot enough to self-ignite. However, according to L.Dutch, the blood temperature does not increase above the animal's body temperature, so it would not be possible to do that. He suggested using a mixture similar to the bomber beetle but in a stronger version as the mixture only goes up to 100º C. But I don't know of any more potent substance that an animal can produce biologically. So, to light the oil I thought of sparks, researched and saw that electric sparks are flammable ​​and then I thought of electric eels. My dragon may have organs responsible for generating enough voltage to create sparks. However, would an animal be able to produce enough voltage to generate sparks, and if so, what would be the complications for the animal itself?

Dragon information: When with the neck raised (like a quetzalcoatlus), the species can reach a maximum of 4 m in height, with a weight ranging from 250kg to 300kg. The wingspan varies from 16m to 19.50. These numbers are because, although the species is no taller than a quetzalcoatlus, it is larger because the neck is thicker which is where the flammable oil will be produced and stored, the tail is larger to help sustain stationary flight while firing (although it hinders flying straight as birds and bats do because the tail would sink and the nose would rear up), it has horns as it makes it more menacing and also helps to attract mates and it also has teeth (unlike quetzalcoatlus). It's a warm-blooded creature. It is carnivorous.

Answer 1

Depends on how big you want those sparks

The voltage required to produce an arc of 1 meter is 3.4MV(30 000 000V). Unless you have a mechanical dragon this is ludicrous to even suggest a creature has the ability to produce this.

The voltage required to produce an arc of 1 centimeter is about 30 000 volts. Only about 38 electric eels at the same time. I don't know if the voltage of electrogenic organs scale with size but this might be more or less possible with a large enough dragon if they do. Perhaps a nice reason for why juvenile dragons can't breathe fire but adults can due to the inability to produce enough of a voltage to create the arcs/sparks if you want that sort of thing.

The voltage required to produce an arc of 1 milimeter is about a 1000 volts. A specific species of electric eels can go up to 860 volts. Not enough to produce an arc that can even be seen, but if it can be pushed up to 860 then it shouldn't be too unlikely for it to be pushed to 1000, maybe 1200 to be sure of a 1mm arc, perhaps many arcs if the two points between which the electricity would jump were numerous. I think this is the most likely to succeed in lighting a fire through a sprayed mist of oil ballpark, and once there is some sort of fire present the dragon can regurgitate the oil in a higher volume than the mist and produce a larger fire, perhaps producing a flame-thrower-like effect.

Edit:

Forgot about the 'complications' section of the question with regards to an animal generating the required voltages.

Electric eels have been observed to sometimes shock themselves, either accidentally or because they can't help it. They have a layer of fat serving as insulation so they tend to be protected from their own electricity but as is observed this protection isn't always iron-clad. It's even possible for them to die from this but my understanding is that the mortality rate by self-electrocution of EEs is small. Should an animal generate even higher voltages, enough for arcs, that animal will more than likely require even greater fatty insulation to protect itself. Then again eels are in water and that might have to do with why they shock themselves so frequently. Maybe a land/air-based animal would not need this layer, but since we don't have an air-dwelling animal to compare with it may be prudent to assume they'll need it. Should they not require it but don't have it and try to generate their voltages underwater then they'll most likely kill themselves, not an ideal situation.

Since the dragon is intended for riding, might I suggest an appropriately designed seat and harness as far as materials are concerned, or rider's suit?