Backup Generator

[Ronmar]

Two strokes, sigh...... I love two strokes. And I understand them.   And they love me back. 

And that is the key to a happy two stroke relationship

[BioHazard]

Doesn't it just have a cast iron sleeve in an aluminum cylinder?

No, whatever the cylinder is made out of is solid. Not like your standard weedwacker or chainsaw engine at all.

What does it mean when a magnet just kinda sticks? Clearly it's not pure steel or iron, or aluminum....so what is it?

[billswan]

Doesn't it just have a cast iron sleeve in an aluminum cylinder?

No, whatever the cylinder is made out of is solid. Not like your standard weedwacker or chainsaw engine at all.

What does it mean when a magnet just kinda sticks? Clearly it's not pure steel or iron, or aluminum....so what is it?

Must be some exotic alloy?

Some stainless steels are non magnetic and some are slightly magnetic, now I am not saying it is stainless just thinking out loud.

How about magnesium with a cast liner that is attracting the magnet?

Interesting subject. Makes me want to find out what you have. Hard to believe a cheap 2 stroke would be made of anything other than aluminum.

By the way you better heed Crofters warning my gut tells me he is spot on and your motor will not like water as coolant when it was designed for air.

Billswan

[BioHazard]

Hmmm...I guess I'll pop the head off and see whats going on in there. The rest of it clearly looks like aluminum, but the cylinder looks cast iron color to me. I have read a lot about people converting chainsaw/weedwacker engines for use in RC model boats, with a very similar small water jacket for cooling. Then we'd have a whole new TC-W3 arguement! I would have to come up with a high temperature thermostat of some sort. At $89 it's hard to go wrong for experimenting...

For those that are interested, the manual on HF's website shows a pretty good exploded view of the engine. I'm thinking about trying to contact the chinese OEM and see if I can buy any parts...
http://www.unitedpower.cn/products_info.php?id=20&type2ID=29

[vdubnut62]

From my experience with harbor freight, they will bend over backwards to get ANY part for anything they sell. The downside is
that it may take a while(read month or two!) But they will cheerfully swap out anything for a new one as long as the warranty is still in effect.
Ron

[BioHazard]

But they will cheerfully swap out anything for a new one as long as the warranty is still in effect.
Ron

That would be the issue. Standard warranty is only 90 days. My extended warranty is 1 year. I have a feeling I'm going to need/want parts in exactly one year and one day.   Plus if I did something crazy like water cooling, I'm sure the warranty is void...

Tonight I ran the little bugger for it's biggest load test. Started at about 950 watts mixed incandescent and fluorescent lights at about 119v. After an hour, it was only pumping out ~895 watts and about 115v +/-. (according to my Kill-a-Watt meter) Is this because of the heating of the gen head? Only used about a quart of fuel during this test...

The highest temp I could record on the cylinder was 269 degrees, and the gen head was only about 100 degrees, with about 40 degree ambient temps. Kinda hard to measure with an IR thermometer because of all the shrouds though...

Interesting note, the chinese company who makes these, United Power Equipment co, was just bought out by a German company in October.

[Henry W]

Doesn't it just have a cast iron sleeve in an aluminum cylinder?

No, whatever the cylinder is made out of is solid. Not like your standard weedwacker or chainsaw engine at all.

What does it mean when a magnet just kinda sticks? Clearly it's not pure steel or iron, or aluminum....so what is it?

My guess is aluminum jug with a steel or iron liner.
Another thing. If they are using nikasil-coated liners and it is done properly they will last a long time. Another benifit of nikasil is it displaces heat very good to alumimun cylinders and in turn you get better cooling efficecy. Chrome bores also last a long time if they are done right .

Henry

[BioHazard]

My guess is aluminum jug with a steel or iron liner.

Well, the cylinder head and crankcase are obviously aluminum. The head comes off seperate unlike most 2 strokes. But whatever the cylinder is made out of is a completely different material, much darker in color, that's why I assumed iron. I'm not sure yet if it has a liner or not, but, since they went to the trouble to cast it out of a different material, I would think it is solid. I should be able to pop the head off and have a look within the next few days.

The chinese-harbor freight style air compressors work the same way, they have an aluminum crankcase and head, with an iron (or something) cylinder bolted in between.

[cognos]

Here's a water-coled head on a Homelite 2-stroke engine, for use in an RC boat. These things are common as dirt in the RC boat world, and work quite well without thermostats, just a water pickup on the rudder, requires forward motion for flow. I don't think longevity is too much of a concern in this application, though...
The company in the link is just one that offers water-cooled heads for engines, and custom work, too.

http://www.majorsmackdown.com/homelite.html

[BioHazard]

I don't think longevity is too much of a concern in this application, though...

Definately...I don't think they start them up and let 'em run full throttle for a few hours while I wander off...

If I could source cylinders and pistons from the MFG, or even Harbor Freight, this little generator could last damn near forever. That is, if they're priced right - if the entire generator is $89, a new jug could be like $20. Problem is they probably want me to buy a container load of them...

I'd surely buy ten of these before one Honda with the same output. 

[vdubnut62]

Harbor freight wanted $27 plus shipping for an engine block/case for one of the 6.5 hp "Chonda's.
I'll bet parts for the little genny are surprisingly reasonable.
Ron

[BioHazard]

Harbor freight wanted $27 plus shipping for an engine block/case for one of the 6.5 hp "Chonda's.
I'll bet parts for the little genny are surprisingly reasonable.
Ron

I wasn't aware they even sold that stuff. Just ask for it at the store or what? The exploded parts diagram for this engine says something like "for information only, not all parts available" or something like that.

[vdubnut62]

I just called up their 1-800 help line and told them the item and part number, also did the same thing when I needed a valve plate for my HB V- twin air compressor.
They have always been very helpful.
R

[BioHazard]

Finally got around to taking the head off. The cylinder is solid, no liner. Looks to be in pretty good condition after 30 hours of use, especially considering it's only rated for a 50 hour durability period.  Looks like the gasket was leaking from the factory. Lots of carbon buildup on the top of the piston and the chamfer on the top of the bore. Just about the entire generator comes apart in a few minutes with a 10mm socket.

[Henry W]

Did you check the cylinder face and bore with a magnet?

Henry