Small Simple Fire project #3

Q 1. I’m wondering about the possibility of starting on the petrol from the generator’s fuel tank and once the gas is coming through to close off the fuel line. I note that most Simple Fire/generator builds on here are started using an electric blower rather than the engine’s own compression when running (apart from a few of Gary’s and other’s earlier prototypes). I can think of a few possible reasons:

The possible difficulties regulating the transition between petrol and char-gas.

The above transition difficulties in light of the fuel in the float bowl or fuel line (this gennie runs for fully 90 seconds after I close the fuel off).

The risk of putting burning charcoal (and possible blow-back sparks) so close to a petrol tank (in a car at least the body work etc. create some barrier/distance).

Can these be resolved and/or are there other reasons for not starting this way? (Like just that the whole point of it is to get away from fossil fuel dependence in the first place!?!)

Q 2. I’ve attached a photo of the air intake with the Kohler filter removed and you can see that there’s a very convenient spigot sticking up which fits some old sink waste pipe I have perfectly!

If I could connect to this there’d be no need to make an adaptor to fit the carb, and it would be much easier to convert the generator back to petrol if I want to (I use it for work and won’t always be able to use charcoal on site so switching back-and-forth easily would be good).

Would connecting to this spigot be a problem do you think? It also means that the fuel line remains in place if I end up using the petrol start up rather than a blower.


Hello Justin! Welcome here!

Looks like you are on a good start. Can we see the inside of the gasifier too? Namely the nozzle. Its the most important part of a gasifier…

As for startup, with the engine runing on the residue fuel from the bowl it will make your head hurt, specialy for a beginer. But there is a simpler way! I started gasifiers many times with a hand powered inflator. You know, the ones fot kitty pools and inflatable boats. They both suck and push air, depending on tha way they are connected, and usualy pull air trugh both upstroke and downstroke


Hi Kristijan
I’m not sure I can post any more pictures yet but for the nozzle I’ve pretty much followed the Simple-Fire design (1" pipe threaded both ends) except that I found a stainless connector with a female thread that fits the end of the pipe, maybe about 2" long, which brings the assembly to a wee bit short of the middle of the reactor.
Had a look online and those pumps look good.
When you say make my head hurt I assume you mean because it’s a complicated thing to make that work? I’m keen on simple like many seem to be here.
With the pump I could have a flare as well…


Q 3. The other photo shows that there’s another very convenient spigot on the silencer (once the cowl and spark arrestor are removed) which just happens to fit the flexible exhaust pipe for the exhaust return!

There must be a reason for all these wonderful flukes? I always feel that things like that don’t just happen by chance! Can I omit removing the silencer (muffler)?

Q 4. I assume that if I do use the engine to get the fire going in the reactor I won’t be able to use a flare, as the gas will be sucked towards the engine not up the air/flare pipe. Everybody seems to be fitting flares as default now, even though the earlier versions didn’t have one, so I’m wondering if someone could give a simple explanation of the importance, or not, of a flare?

OK this has got a bit long now so I’ll post it before the evening is gone. Lots of questions I know… that’s always the way with beginners… you just have to humour us!



I think you can, just not all in one post.

Once the gasifier is burning and it makes good gas, its not that hard to start the engine on pure woodgas. But if you got petrol from a carb in the equation its like trying to run a engine under constant choke.


Aha as you can see above I’ve been able to get questions 3 and 4 up, with the photo as well. That’s the last of my original post.
I should have used the reply feature from the beginning that would have kept it all on one thread as well. Such shenannigans!

1 Like

That’s what I feared. Like two positives making a negative.
So you would have to get rid of all the petrol in the float bowl before introducing the gas, which would in turn have to happen at exactly the right moment.
Mixing whisky with wine comes to mind…


You could also get a 12v mattress blower to start up the system, but Kristijans hand pump idea would be great in a total emergency need.
Luckily Charcoal doesn’t take too long to produce engine ready gas.

1 Like

In my Charcoal powered Mazda B2000 I have a Weber Carburetor and do start up on petrol. What I do is run the engine on petrol and light my nozzle, setting the air mixture so it pulls a draft for lighting. When I feel like it’s running rich or the nozzle area is well lit I’ll shut off petrol fuel supply.

Typically what happens is the engine dies but then I just play with my air mixture and try without the petrol. If I get lucky it’ll be ready.

The engine will not be happy with such a rich mixture of both petrol and producer gas but since it’s only idling with no load it puts up with it.

1 Like

Hi Cody, if one can hear the difference when the gas starts to reach the engine (petrol and gas together), could I close off the gas (as close to the intake as possible) and the petrol too at the same time, so that the extra fuel in the float bowl is used up. Then when the engine dies reopen the gas and start the engine again on that?

1 Like

It wouldn’t hurt to try. But I just wait until I see good color coming from my nozzle and shut off petrol, and wait for the float bowl to empty. So that gives you an extra bit of pull time for perhaps better gas.

1 Like

I would just leave the producer gas hose open though.

1 Like

Ok that sounds like it’s worth trying then as a first attempt for testing purposes at least. Then I can add blowers or whatever later. Though I think I might get one of those two way pumps anyway as a back up in case it doesn’t work (and in case there’s ever no petrol available…)
When you say good colour coming from the nozzle do you mean like a glow that tells you the reaction is going well in the charcoal?
Actually I’ve still to get my charcoal production sorted in any case before this thing can take off, so it’s going to be a while.

1 Like

Charcoal size is pretty important. I tried to cut corners with “good enough” sizes and got poor gas.

I bought a cheap electric wood chipper that isn’t worth a toss with wood beyond twigs. Works wonders and grinds the coal to flakes. I’m thinking of finding a way to make it manually powered in the future. The Sunjoe brand with the 17:1 reduction is what I got. You can find them on eBay refurbished for not that much relatively. I use a window screen to sort the dust away and just about everything that runs through it is below the 3/4" maximum size.

1 Like

Just had a look but unfortunately here in the UK that brand doesn’t seem to be available. I’ll hunt around for something similar.
I’ve got some 1/8" mesh on the way for a screen though so even if I have to use a couple of bricks for my first firings the stuff should be the right size.

1 Like

It might be a different name in Europe and the UK. Just look up electric wood chipper and find the cheapest result. They’re Chinese made so I’m sure they’re exported to your side of the Pond as well.

1 Like

Oh yes plenty of cheap chippers over here.
I generally hate cheap crap but one of the really great things about this forum is that you are all working away at finding real uses for these things. Cheap chipper: no good for wood, but great for charcoal!
Anyway please don’t think me rude if I don’t reply for a few hours but it’s a bit late here now so I’m off to get my beauty sleep.
Thanks for all your help for now.


Ok did a couple more hours of work on the gasifier today and also took some photos of the nozzle.

do you think it will be a good one? Found it on ebay.

Couple more pictures of the proceedings today, mostly assembling and sealing things up with the silicone + some very sloppy brazing.

I’m wondering whether that cyclone is going to be too small…


If it is aluminum then it might corrode over time faster than steel would. That nozzle is alright for getting used to it but what some guys do is make a steel flute.

You could adapt this into your system as it is. Take a length of steel pipe with two or three holes pointing in the same direction. You could just cap off the end of the pipe flute.

Just screw that pipe into your existing flange and point the flute holes upwards.
The Gilmore style nozzle works in an emergency but will eventually burn away.

Some guys use a singular nozzle pointing upwards from the bottom but the flute does essentially the same thing with sideways orientation.

1 Like

I remember a while back I skimmed some posts about flutes but didn’t really take it in. How come the flute doesn’t burn away like the plain nozzle? Is it the multiple holes spreading the incoming oxygen around?
So I just had another look at some of the threads on nozzle design but they run to many thousands of posts! I could be in there for days! Any chance you could give me a rough idea of the generally agreed conclusions on hole size and positioning?

1 Like