My gasifier WILL NOT LIGHT….Arrrrgggh

It’s an embark box. I was a civie embedded with the military for a number of years. They gave me the box to pack my tech gear on deployment. I agree that it may not be air tight. I added seal inside the lid, but thinking I need a better on along with a tighter lock down for the lid.


This is my fima gasifire


I think its your fan


Some silicone over the leaking welds and any possible leaking areas will probably fix the leaks. Once you are away from the hottest gas you can use the cheaper caulking type silicone.

As a test, on the box at least, I’ve gotten away with duct tape to help seal leaks. In the video I posted earlier I had a plastic bag taped to my clean out port because I hadn’t made a cover for it at the time I made that video. Looks like I used electrical tape to hold that bag in place. I did have something shoved in behind the bag to help shield the bag and it was just an impatient first flare test but it worked.

I agree that for a small engine a charcoal gasifier is probably the way to go but the gasifier you already built should at least get you flames. I didn’t notice if you said what you are using as fuel. The size of wood could make a difference as well as if you have a good bed of charcoal (glowing coals) built up. Too big of pieces can let too much of the carbon dioxide or even air get through without being turned into flammable gas.

If you can reverse your blower or use another source of air to blow air into the outlet side, it should turn the gasifier into a forge and really get your wood burning and build up the bed of coals. Then you should have good gas when you are sucking the gas through like it normally would assuming you get rid of any leaks.


You may want too start with charcoal below the air inlet nozzel- that is how most woos gasifiers start out-- or ir we run low on wood and burn up our charcoa than we always bring charco up to the air nozzels before adding in raw wood- also wood must be around max 25% moisture.


The FEMA chart said 6” burn tube @ 18” long would drive a 30 hp (500cc) engine. That seemed like a good starting point, so I went with that. Now I’m thinking I a
Have an old 17.5 hp (262.5cc if my math is correct) riding mower that I would love drive on wood. So ultimately I’d like to salvage as much of this build as I can to do that task.


FYI… I’m using wood pellets that have been stored in a typical Florida humid environment…
Todays plan is to go over the entire system and find any and all leaks. So…beyond that- Is there any concern with the design itself? Is a 6” burn tube too big? Is the plumbing size in question? Any other things I should change?


i have never seen such high hp related to this size in ccm…?


Located in Florida, Fuel drying will be a constant vigil, Moisture may be your source of frustration. Sunshine and warm breezes are the tools you can use for fuel drying, keep unused raw wood fuel covered and even in a dry, moisture resistant container. Once you build a charcoal gasifier and get used to burning in it, you can use the moisture in your charcoal fuel to make richer (more Hydrogen) gas. You are already learning!! :cowboy_hat_face:


Good Rick. Finally you have layed out the basics of your “Will NOT (make gas that will ignite) LIGHT”.

First you used a F.E.M.A. as a basis design that should be properly renamed: The HEARTBREAKER.
Next you are using manufactured wood fuel pellets that all who’ve used for engine capable fuel gas have had to specially design for; around their weird burning characteristics. Actual wood: chunked blocked up; or coarse chipped and screened sorted, is relatively easy to gasify.
Pellets are not.
But now that you’ve stated your intention to IC engine fuel there is hope for you.

O.K. using as a starting point what you have so far . . . .
First set aside the wood pellets. Make or obtain some actual wood you can chunk block up in some way.
Next realize that wood gasification requires finite controlling the air in allowed. It is an intentionally air starved process.
Your F.E.M.A. design was based around the concept of so-called “Stratified Gasification”. Fancy talk for starving the air allowed in, not with restrictive to specific point air nozzle jets. But as jet-less; using the wood fuel stacked above as the allowed air-in restrictor.

That picture you’ve shown with the hot glowing burning pellet bits is making fully combusted no-energy-later, spent combustion gases. You/we should never be able to see that as there has to be a tall air restricting fuel stack above that in a Stratified system. This fuel stack IS your air-in control being jet-less.

So measure whatever internal diameter of 'firetube" you’ve made up and cut/chunk up real wood into chunks no larger, or much smaller, than 1/7th of that diameter. Don’t have to be tablesaw precise. They can vary some. And will work much better as irregular shapes. Easy way to do this is saw bits lengths of branch limbs. Slice thin discs of the major trunk and trunk leaders. Then whack chunk those up with a hatchet.
Next easy way is to electric chainsaw up wooden shipping pallets. Cutting out the nailed sections. NOT using those (the burnt free nails will downward flow and clog up more fuel bits from falling down). Farther size reducing the chainsaw made sections with that hatchet, your friend. Mind the fingers.
Chain sawing either way make strand-chips, useable as a filter media.
Narrow blade sawing will make unusable fine sawdust. (What the pellets were made of.) Wet; and all gasifier systems are wet insides; and fine sawdust cakes and clogs flows.

Do preload that fire tube: bowl-grate and up at least 4-6 inches with 1/4" to 3/4" chunked up real wood charcoal. Once that is burning red dump in your wood chunks up to the top. It will need at least a 24" stack above the char. Let it settle in burn for 10-15 minutes. Then It will flare. Then it could engine fuel run.

Have an on hand a basket/box/bucket/sack of those wood fuel chunks always. Top off restore that air restricting stack as it is used up; settles; and you do have to rod it down for lower burn voids made.

That will be your first indication that FEMA’s are babysitting hand-holder to use and operate.
The used up lower charcoal left behind ash clogging flows requiring periodic grate shaking will be another:What!! This RPLS really is an hand holding HEARTBREAKER!!!
Steve Unruh


Oh yeah. To shut down having to had keep that fuel stack above maintained that this design forces; you will have a made up truly air-tight top cover or cap. To stop all inlet air flow wanting to shut down.
Otherwise the lower combustion area zone will just keep burning upwards when no longer blower/engine flows pulled down.
And air blocked shut down is where you will really find your construction air leaks!
Visible smoke emitting once top sealed up if you are lucky.
Very tiny small minor leaks and you will be unlucky coming back to it all having burn up to clogging ash. With maybe that Hot, HOT all charcoal burn heat warping your metals. Cracking your welds.


Like I said build a charcoal gasifier, a wood gasifeir is not going to work. We have all been here with millions of ideas and all wanted to run on wood fuels. You are not unique. Build a charcoal unit your perspective will change. Its not harder and there are many benifits that outwiegh any cons of charcoal.

Once you have built a unit then start to plan a wood fueled system. Small scale wood fueled systems must be automated or it will not self sustain and even then it will only be marginal. Fuel flows must be constant otherwise you will make tar.

If you are over 1000cc then a wood fueled gasifier will be viable. Under 1000cc charcoal is the way to go.

Take the easy road, we here have already paved that road for you. If you continue with woo fuel on a small engine, perpare for bumpy road and lots of challenges.


Thank you guys… What I’m hearing is beginning to brighten my dim light bulb of knowledge. So, I did notice my fuel pellets being consumed and burning upward in the tube. That’s when I actually lowered the pellet level to try and see if I was getting any downward air flow. It seems like it was just a small fire with the flame licking up, not being pulled down. At that point I figured I just wasn’t drawing enough air and redesigned my fan system. Originally, I had built a Venturi inlet into the pipe (see pic). I declared it a bad idea and put the fan in line. I figured a higher pull would keep the fire moving down, but alas…no joy. So then I figured, maybe I’m pulling too much air and added a fan speed control. No joy, and now we’re up todays theory of air leaks.
As you can see, I’ve been wrestling with this no light through various evolutions of thought and design and still getting outsmarted by an inanimate object.

Also, somewhere in this process, I had two back to back burps, throwing hot stuff back up the tube. Very exciting, especially the second one where I was looking down the tube to see what was going on.
I’m currently resealing everything I can. More to follow.


Awesome. The good news is, I’m on a few acres of land with lots of potential fuel. I have chainsaws and a log splitter. The plan all along was to use my homegrown fuel. I just got STUCK trying to get this thing working.


This too I kind of figured out. I have a steel cap for the burn tube and I cap the flare end. Seems to extinguish it fairly quickly. Thanks again for taking time for my struggles.


Steve U,
Do you have personal experience trying to run a FEMA or just lots of experience trying to help others operate theirs? As usual, it sounds like you know what you’re talking about.


Here Rick is a link into Flash001USA’s four+ years evolving from a jet-less FEMA beginnings; to adding jets, lids, and later four stage downstream filtration:

Go back on his channel and do see he was finally able to small IC engine generator run for his battery bank recharging a couple of years previous to this video.
Come forward a couple of years from this video and see his added electrical/electronic controlling MattR refers to.

For truly small engines like you proposed; do take MattR’s and others hard won experiences and just go with charcoal and be there in 1-2, maybe 3 steps quickly in weeks. (Ha! Ha! The charcoaltier’s still fuss a lot about nozzles: where to place; materials; and durability.)
For raw wood gasification truly a work loaded 500cc engine generator should be the minimum. And a 1000cc V-Twin or inline multicyclinder will be the better easy to achieve on raw wood.

Ha! And then be stunned watching guys having built large tractor and pickup truck gasifier systems then produced gas fueling really small generators for hours and hours on their big engine’s woodgasifier system that have been pulled up hot to optimal internal working conditions.

Florida living Sean French once said here on the DOW he had; and could; make small engine gasifiers but quit. Weary of making all of the correspondingly tiny wood fuels bits for them. Back to that 1/7 size fuel bits ratio to hearth internal diameter that Dutch John had discovered and published out.
SeanF. said he’d evolved even past this Ford Ranger OHC I-4 onto older pushrod Chevy V-8 systems by then. Easy, pleasie, to run his hurricane outages electrical generators on these then he said.


Resealed EVERYTHING today. 40 minites after getting it lit…no joy. I make smoke only. If I hold a torch to it it shows yellow, but won’t light. Still using pellets. Maybe try again with chunks?


Your grate is probably packed by now. Thats unless you have cleared your grate at some point? It dont take long to pack the grate especially if you have been under pulling it. Tar will saturate the char and it will just plug up.


Also what is the depth from where your oxidation point is to the grate?