Is this the generator I should get for my gasifier?

I haven’t finished my gasifier yet. However, I’ve also got no usefull engine to use for my gasifier yet. So what comes first? Usefull engine for my gasifier, or a completed but useless gasifier.

I’m looking at a “Powertech 6500W” generator. Pull-start 135 euros, electrical start with battery, 170 euros. This generator comes with a 6.5 hp “hondaclone” OHC 4-stroke petrol engine. Peak electrical output is rated at 2500 watts, constant power should be 2000 watts. 220 volts, 12 volts and 380 volts connections.

I do think my small gasifier should be able to run the engine itself. Project discussion can be found here: Small gasifier project If anyone can confirm it “should” be good enough for this generator, that would be awesome.

But I also wonder about the power output. In the past, I had a generator like that. (it got stolen…) I could stick-weld with that generator, using petrol. But the energy value of gas produced by a gasifier, is less then of petrol. So how many watts can I expect from such a generator, using woodgas? Will it provide usefull amounts of power? Can I use my really cheap “130” flux-core welder? (lots of flux-core welders with “130” on them, hope I provided enough information)

Any feedback would be really nice!


I had one too, and it got stolen too. The few times we used it, he did ok. Big grinder/flex 230 mm cutting stones was no problem. The price indicates it is a trow away product. If it is broken it is cheaper to buy a new one then repair. Small generator…Simple Fire…?

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What do you mean? Also, did you use your generator with a gasifier, or just on petrol.


I figure that you get about 1/2 the power from wood that you get from petrol.
Regarding the difference in price for electric start versus pull start:
If you are young and physically fit and enjoy a challenge, go with the pull start.
Otherwise, I’d suggest the electric start no matter which generator set you choose.
Why?: Since you are just starting out with woodgas, you may be doing a LOT of cranking until you get the system working well.

Pete Stanaitis


The generator is rated for 2000 watts continuous power delivery, with peak set to 2500 watts. A 6.5 hp engine is about 4.5/5 kw-ish. So is there always this 50% efficiency loss while using an engine to turn a generator? Does this mean this generator on woodgas is only able to produce 1000 watts continuously?

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No, no woodgas for me yet. Like everyone to busy working and getting the list cleaned up for something new. Hard working on the heatsystem for the house, almost there, generator connected but wont start (hydraulik starter and nothing available to convert it to 12V).
So, generator does what is for, but for a few 100 euro it is unsure how long it will run. Chargas because it is really easy and that is how the real guys are doing it. And if I read it right, no powerloss on charcoal. Correct me if I am wrong please.


I’d say “yes”. About 1000 watts in your case. Once you get deeply into this sport, you can start to tune things to make some improvements, though.
I’m sure the experts will be along to correct me, Joep, but I don’t think chargas has much more power (Btu’s per volume) than does woodgas.

Pete Stanaitis


And when I’m trying to get to the origional rated watts, it will just stall the engine, because it can’t keep things running… Right? No actual damage will be done to the engine itself because the fuel is of much lower grade then petrol?


You loose some power with chargas. I was able to get about 1200W from a 3000W generator. I think you will never get full power.
Producer gas is actually a gas. Gasoline, or petrol, as it comes out of the injector, is a liquid in droplet form. It is NOT truly in single atom size particles. This ‘atomized’ liquid occupies far less space than do truly individual molecules of producer gas. So an engine running on an atomized liquid fuel such as gasoline can draw more air into the cylinder and produce more power in each combustion event.


A base unaccounted factor Jahee.
Your voltages say you are 50 hertz.
I and most other responding are 60 hertz.
The difference? Your 3000 RPM generating running will have less power loss set back than 3600 RPM running.
My friend Dutch John always beat me on power equivalencies no matter how much more extensively I would engine systems modified.
And my modification then meant no more gasoline operating possible. You want to do just a one weld repair; or one bead lay down modification . . . . then much time to get a gasifer system up, stable operating; to do that just five minute job.
Still gasoline/propane capable just crank her up and do it.

If you must wait collecting up money go one generator engine size up to get a true on producer gas 2000 watts loaded capable. Able then to just do a carburator air-box mixer.


When the gas quality of my gasifier starts to drop, my genset tries to maintain rpms by opening the throttle more. When it can’t keep up, the engine slows down and eventually quits if I don’t do something about it. In that case, I don’t experience any engine problems.
My generator sets are all old Onan 2 cylinder, 1800 rpms units. So my experience is limited to them.
But, what if you are running some sort of appliance that REQUIRES full voltage and frequency for proper operation? No guarantees there.

Pete Stanaitis


Well Jahee you did say any feedback.
Your profile says unemployed. I would assume you don’t have money to spare. Why not look for an electric start engine that is used? Maybe a free one. Build your gas producer to power that.
Forget about those cheap generators. They are annoying.
If you are broke, you can belt a motor to the engine, add capacitors and make it produce power. A nice 10hp three phase 1500rpm motor would be ideal.
Can you get a motor given to you?
Pete pete pete, listen to Pete. Electric start.
It is a miserable experience to try to switch from gasoline to producer gas with a carbureted engine, while running, especially if one is learning the art of making gas.
Or in another words, in the beginning gas quality will be bad, and your engine will stall.
If I had to do it all over again I would build the producer first and make it work with a fan and then make the flare burn properly first.
Then any engine will work doesn’t matter what.


Thank you for your feedback (all of you)!

My GF is considering this specific generator as a gift. And to me, it’s a very expencive gift. So I want/need to be sure this specific generator meets my expectations. I don’t want to get it gifted to me, and then complain about how horrible it is. Both my GF and me need to know what I can expect from all of this. It’s budget, it’s chinesium, it’s not long lasting when used on a build-site.

That being said, I now know what I can expect: ~1000 watts, which is enough for some of my tools. And if I need the actual rated power, I’ll have to switch back to petrol. It’s a must to have the electric start. And in the end, it should proof I can make a functional gasifier, or not.

You also mention I should look at some stand-alone regular used 10 hp engines. About once a week I do check our online marketplaces. However, there are very little engines out there. And the ones that are out there, are really expencive for what they are. Alot of boat-related engines aswell. But to pay 300+ euros for a junk-looking engine… No, just no. (I’m also horrible with electronics)

On your bad quality gas during start-up comment: I’ve made a fan and a flare unit. So I do plan to start up my gasifier propperly, create at least ok-ish woodgas, and then try to make an engine run on it.


Slightly hard to follow, but I do understand what you are saying. I am indeed going to make an “airbox mixer” with some PVC ball valves. I also have the option to put an fan/blower in the loop, pulling the gasses trough the gasifier, if that would be helpfull.

A “one size up” generator will increase the purchase price by alot, and my GF is considering gifting me this specific generator. It would be a good “proof of concept” generator, with a fallback option to go on petrol again.

This generator uses a 6.5 hp “honda clone” OHC engine. When I would need the full 2000-2500 watts, I think I can just replace this engine, with a (cheap-ish) 15 hp 420 cc hondaclone engine. That way, if the engine runs on gas and only produces half of the power, it should still be able to spin the generator part itself at it’s rated output.

All things together, I do know now what I can expect, and what my options are. Thnx for all the feedback!

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Ahhhhhh, the rest of the story.
The decision has been made. There is only one possibility.
All this “feedback” wasted yet again.
I think perhaps there is a much better question that we, here on the forum, can answer. But what could it be?
Does anyone know how to prolong the life of a Chinese engine?
Does synthetic oil help?
Does taking it apart before running it, and sanding any rough edges help?
What is the easiest way to unstick a tarred up engine?
Jahee, what is your real question?

Rest of the story? Part of it, yes.

The decision has kinda been made, after getting all this feedback. It’s really important to me. Obviously I had heard some things about power drop. But mostly in cars, where it’s just a “slowing-down of things”. I had loads of clues, which needed to be confirmed or debunked. Feedback isn’t wasted AT ALL.

I’ve also seen many vids from youtubers such as AvE, Musti1 and Cards and Cameras. There they often play with engines. They explain well enough what the downsides of Chineesium parts are, and who should/shouldn’t buy them.

My “real questions” for today have been asked, and answered. I am really happy with the feedback. Once I’m at a different stage, new real questions will be asked in a new topic. I had guessed this engine was good enough for now/current situation. It’s experimental. And I know what to expect.


Go bigger on your generator. This is already going to be challenging enough and trying to run a small engine is about as difficult as it can get. This size engine will do well on char gas, but unless you really have your gasifier sized and dialed in to run this small of an engine it will be difficult.

A 400 cc range engine will be good for all around use without going to big. Your little generator will not even achieve 1000 watts at 50 htz it will be basically worthless.

It is not about efficiency loss entirely. Its about how much energy woodgas has to offer verses what petrol has to offer. Add on top of that there are efficiency losses with the vacuum pulling sucking on your gasifier too boot.

I agree with Pete, if you factor 50% this is about what you could expect reliably from the unit. However, when things are working well you can certainly achieve better, but that just will not be all the time. There will be times you will get less than 50%. Keep in mind this is a solid fuel machine and the physics are always working against you.

Oh yeah, get the electric start you will need it after you yank the pull cord right out of the generator.


Good Morning,
Other factors advantages to an larger engine generator set.
Go electric starter, yes. On the smaller units this will at least give you the toothed flywheel.
But on the smaller engine the actual starters are tiny and fragile. You will wear it out or break it with extended cranking dialing in wood or char gas.
Larger units by necessity have better electric starters.

All engine will soots blacken and thicken their lubrications oil quickly. Not especially harmful. But I’ve had many now that the cranking speeds camshaft compression release mechanisms would stick non-effective from the soots thicken oil. And that HURTS hand cranking. And breaks the smaller starters, jumper battery boosted cranking.
Just change the engine oil often as it blackens colors. Use a proper called for thickness oil. And on woodgased set up I use not synthetic but standard mineral oils. Why? Cheaper. Then I WILL change them often.

Last reason. Bigger units are heavier. The next thief you want to have to bring 2 other friends and then clown-fest trying to move your unit through tight places. Better chance yours will be left alone. Or the cursing noises get them caught,


Another thumbs down on the generator. I am just now involved in this process. Running a 6500 watt generator on chargas. Not hard to do but I still haven’t been able to produce enough power to run a 160 Amp inverter welder for more than a few minutes. Will run 1500 Watt saw. Pull start on chargas sucks. Like Bruce said, getting switched over from gasoline to producer gas is pretty tricky as well. As for the Chinese clone engines. I’ve run the Harbor Freight preditors with no issues. Most of that stuff is either going to break right away or give pretty decent service. Right away means about one day after the warranty is up. I’m real displeased with my Generac generator and I’m betting you will be way more displeased with something cheaper and smaller.

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Can you use your welder for longer while using the generator on petrol? Secondly, I see a large amount of these types of generators I’m considering. Almost all have “6500w” in their model name. Alot of newbies (like myself) expect it’s an 6500 watt generator. However, on closer inspection, it’s just a 2000 watt constant power generator, with a peak of 2500 watts. And I looked up a review/fix of the one I’m looking at. (it too has 6500w in it’s name) However, the guy reviewing it was told it’s indeed an 6500 watts generator, while it had electronics in it going from 1500 watt to 3000 watts only.

If in fact your 6500 “watts” generator is in fact a 2000-2500 watts generator, being able to power a 1500 watt saw on chargas, is actually rather good?

(if my assumptions are very wrong, please let me know aswell!)