2 stroke petrol generators

[starfury1]

Hi all

Not strictly speaking an electronics device...really electrical

Ive got a petrol generator that doen't seem to be able to deliver current at high amounts.

Its an el cheapo one here

850W job
it seem to run a light ok

Does anyone know of info out there the net on how these things work
or know the most likely failures of these beasts.

perhaps a testing procedure for them

its crude and electronics seems non existent in them.
(don't expect a nice inverter there isn't one me thinks)

Downside is I am fairly certain that it will require specialized parts for repair.

I am not sure if maybe too much current has been drawn off this but there is a breaker so suspect if that was tried it would kick out.
(I think they use it to run a heavy duty power drill off...maybe thats what killed it...dont know...not sure if they are suppose to run a load like that off it)

Know stuff all on them so any help would be greatly appreciated Thanks

Cheers

[tvtech]

Re: 2 stroke petrol generators

Most likely the voltage regulator is at fault since it has some output.You may be able to troubleshoot the regulator however it is usually best to replace it.

[Maxxarcade]

Re: 2 stroke petrol generators

I've heard of a failing exciter coil causing this problem. Not sure how to fix it on that particular model though. If it is a permanent magnet generator, it would probably be the brushes. Just going by what other have told me, I haven't been inside too many myself.

[stevo1210]

Re: 2 stroke petrol generators

That petrol generator looks like the one I saw at Bunnings warehouse the other day. I also noticed that it's a 2 stroke one and not a 4 stroke generator.
I think that if theres too much current being drained off the generator, it will start to cut out. I don't know why you can't power a drill though....

[starfury1]

Re: 2 stroke petrol generators

Thanks Guys

Yeah I got no real idea on how they work and as for electronics...what electronics
(I was sort of expecting an inverter of some kind...but no)

The only think I could find was a 12 UF 350V cap (not sure of what type it is) in series with the Active or Neutral
(for want of a better word)
(I did find some mention of this playing a roll in regulation, but I got no idea)

Stuff all tech info on them on the net. (that I could find)

this unit is not that new but had very little use
it is possible they could have been pulling too much from it although I would have thought the circuit breaker would have kicked out if they did.

I think conceptually, its an electric motor used in reverse...so I'll have to look into electric motors and refresh the rusting Grey matter)

yep I am a total Noob on these

Thanks and cheers i'll have a further look at it

Edit: yep stevo its a bunnings job and it is 2 stroke (mix oil with petrol)

[PCBONEZ]

Re: 2 stroke petrol generators

It's rated power is only 650 watts. (850 is peak/surge not 'running')
That is only about 2.9 amps at 220v.

When you go from unloaded to loaded you should hear the engine slow down then speed up again. It should happen fairly fast. - If that isn't happening the device that controls the throttle may be fubar. (There are numerous different kinds so I can't offer much more guidance on that.)

Also it's an AC\DC output.
Is there a device to switch between them or just different jacks.
As in: You aren't using an AC drill on a DC generator R U?
[Remember I can't see what's going on.]

[starfury1]

Re: 2 stroke petrol generators

Thanks

You aren't using an AC drill on a DC generator R U?

Yes mate a good question to ask and yep thats why, you can't
(and it wouldn't be the first time something very simple was the answer)

No its plugged into the AC 3 pin socket

You are quite correct it does do DC but thats jacks on the side away from the AC

Thanks for the correction on the Wattage

I'd hazard a guess, and say there is probably a zillion companies selling the same unit under different names with cosmetic changes.
(seems to be the way of things)

I think it may have been reeving up and down but I'll check that out too
Next time I have a look, I'll get some photos.


Cheers

[999999999]

Re: 2 stroke petrol generators

Lots of things could go wrong that are engine related, "maybe" (I have no idea the degree of RPM monitoring. I'd look at the general engine maintenance items if you hadn't yet, as they need periodically tended to anyway. Fuel filter, air filter, carb mix adjustment, etc. Check the frequency of the output.

If you are SURE your test load is within the max current of the unit you might also temporarily jumper the overcurrent shutoff switch out of the circuit (to test, not to use it) or at least measure it's resistance. Depending on what the fuel line is like, on many 2 stroke engines I've observed that the fuel line is cheap silicone tubing that rots (from the oil in the gas maybe?) to a brittle state which can produce pieces of it in the filter or screw up the air/gas mix ratio because it's not pulling through the filter anymore (if filter is at tank end of the line). Check the spark plug.

Did this generator previously power higher loads than it does now, has it's performance degraded or had you never loaded it to this level you find problematic with the same type of load?

[PCBONEZ]

Re: 2 stroke petrol generators

When you are doing that maintenance don't forget about the spark plug!
-
2 strokes LOVE to foul spark plugs!

[starfury1]

Re: 2 stroke petrol generators

Thanks too 9's

That part is seems to be running fine. (motor)
but since the two are inter related I wouldn't rule out a possible prob

Did this generator previously power higher loads than it does now, has it's performance degraded or had you never loaded it to this level you find problematic with the same type of load?

From what I am told it should able to handle the load I put on it but I have yet to do any accurate measurements on loads.

I have at this point only done a few quick tests

I am wondering if it may have been being used on a load that was a bit much for it and it killed it

true thought, the 2 strokes love putting crap on them (spark plugs)

Been off and on raining here so Haven't got back to it
(we all know how environmentally friendly 2 strokes are (not!) so not going to fire it up indoors )

Thanks guys

Cheers

[stevo1210]

Re: 2 stroke petrol generators

(we all know how environmentally friendly 2 strokes are (not!) so not going to fire it up indoors )

Two stroke devices emit smoke like crazy so you could start it indoors but have the exhaust face out the door?.
I know what it's like with a 2 stroke machine turned on indoors.... it happened last time when we were trying to fix a 2 stroke whipper snipper.

Been off and on raining here so Haven't got back to it

It's also been raining here down in Sydney. It's the middle of November when it's supposed to be hot!.... and it suddenly just rains and rains.

[starfury1]

Re: 2 stroke petrol generators

Thanks Stevo

there no screaming rush on it so not to phased about it
I've had other things to do also

but yep its a smoky beast

[PCBONEZ]

Re: 2 stroke petrol generators

Must be the week for rain then.

I'm in AZ, Phoenix. - Desert.
It's usually so dry here that rocks drink water.
Poured rain for two days non-stop...
.. two days ago...
.. it's STILL mud outside!
.

[starfury1]

Re: 2 stroke petrol generators

we need the rains badly but mostly its misses were its most needed JCM scarcrow isn't far from the truth out west here...one bloody big dust bowl
so I aint complaining

WE have had a fairly dry winter and with the summer here bush fires are common...so the wetter it is at the moment the better
think our summer is going to be another hot bush fire prone one

AZ from what I have seen of that place on Tele Dessert is an understatement, rocks drinking water

[999999999]

Re: 2 stroke petrol generators

That part is seems to be running fine. (motor)
but since the two are inter related I wouldn't rule out a possible problem

From what I am told it should able to handle the load I put on it but I have yet to do any accurate measurements on loads.

I have at this point only done a few quick tests

I am wondering if it may have been being used on a load that was a bit much for it and it killed it

true thought, the 2 strokes love putting crap on them (spark plugs)

I was wondering if the engine responds correctly to the increase in load, if it maintains the same RPM but a bit more detail about how this is designed, the power generation portion, might help.

Since we don't know exactly what it's like, it's tough to speculate, but it still supplies lesser loads so I don't think the idea of "killed it" would apply in a strict sense.

It could be a lot of things though, even something as simple as oxidized mechanical contacts/connectors that need cleaned off (and if bad enough, perhaps tinned to reduce future corrosion, generally to tin something like that you'd rough the surface with fine sandpaper then apply a ton of flux and only a tiny bit of solder spread around with an iron tip, or use tinning flux).

Similarly so with the overcurrent cutout switch, if it's contacts had degraded over time it might be a current limiting resistance that, through pulling more current, heats up the contacts and further degrades them. IF the overcurrent cutoff switch seems to be the problem, you might get lucky and it has a frame that pops open and the contacts can be polished with some brasso or similar on a cottom swab, drilling out a rivet if there is one then you'd need a thin bolt and nut to replace that later, or of course to source a replacement cutout switch.

I would just start with a maintenance overhaul, cleaning the air filter and partial disassembly to inspect everything you can up to the point where there's a lot more work (taking carb, cylinder head, etc out might be overkill but maybe spraying some carb cleaner in is a good start, and pouring gas all over the carb intake area to wash away the grimey oily builtup (then relubing any springs which may need lube that the gas washed away)). There are so many various things we can't begin to know like if the generator has a short in it's windings or ...

[starfury1]

Re: 2 stroke petrol generators

yes "killed it " being that lovely term that applies to everything
(or more likely, stuffed if I know)

From what I understand it hasn't been used much but has been sitting for a long time.
so yeah lack of use maybe part of it...it had been getting a workout and working fine from what I understand before it gave up the ghost.

Corrosion of contacts etc is possible

Thanks 9's and yes again you are quite right...it could be many many things

A general service is probably a good starting point regardless

let you know more when I get back to it

Cheers

[hardwareguy]

Re: 2 stroke petrol generators

The cap you found is to snub the horrid noise that comes out of a cheap alternator, especially if it has brushes. With that in place it might be possible to run some simple electronics but a PC would need a GOOD PSU that can take a lot of crap.

A drill should run just fine.... most are only about 400-500W. I'd clean the carb and check th throttle linkage before I checked the wiring. As the above poster stated, listen for the engine to slow down and quickly recover to take up the load.

[starfury1]

Re: 2 stroke petrol generators

Thanks hardwareguy

I've yet to get back to it...I can assure you I wont run my Enermax Liberty on it

Yeah that was what I did a quick test with and it ain't got no grunt.

The light bulb worked OK
(but that as you know is stuff all as a load)

I will pay attention to whats happening with the motor when I try it out again

Dont think it will be this side of Christmas thought...

Cheers & Merry Christmas All