WW2 US Army Homelite Generating Set

Great news that it has life again, and I'm sure once you've re-built her you can tinker and get her running without any problems. Good luck with the genny side as I'm lost with all the wires etc but I'm sure it will still be interesting to read how you get on.

Stu.

Certainly took your time getting it fired up!!! I thought the whole thing would be finished by now

Well done though - did you do a video of it?

Now you've got me wondering. That tap on the crank case was connected to the aux fuel line on the tank before wasn't it?
If so, maybe they need to be connected again. Once the engine is running maybe you are supposed to turn that tap on to keep crank case pressure going into the tank?

It may sound completely wrong to lose all your crank case pressure but you never know, it might just be crazy enough to work or it could just be my mind working overtime after a few too many ciders

One of the only useful bits of info I found about these was that the tank was pressurised using crankcase pressure...

Connect it up, prime it, start it and turn on the tap - worth a go...

Personally I don't see that it can work, as the tank is vented, but I've got some gas hose that's about the right size, maybe worth a try.

I've had a look & I reckon the problem is fuel starvation. I know a few of the American sites claim these are a pressurised tank, but that's generally speculation. I've had the fuel system apart & I'm pretty sure I know how it works.

I think we've got a pipe bent slightly out of shape in the carb & it's not depositing fuel in the right place. I suppose now would be a good time to give my version of what's going on in there....

Yep, do some diagrammes while you're at it too

Right, here's my understanding of the fuel system for this engine....

Let's start with the tank. On the underside we have the fuel tap (the upper bit sticking out in this pic)....



Below that you can just see the fuel reservoir, which is connected to the tap by this pipe....



This fuel reservoir runs through the tank as a brass tube, but is only connected to it by that pipe & the tap (which has a screw-out filter BTW). Here's a pic of the top of the reservoir, notice the 2 pipes to the left of it....



These 2 pipes are soldered or brazed to the outside of the tank, & both go into the tank in diagonally opposite corners, where they are terminated just inside the tank, on the roof of it, so to speak....



The other bit you can see on the top of the tank is the top of the fuel tap rod, this is inoperable, but the tap is stuck open, so it doesn't matter. Now those 2 pipes may end up together at the top of the reservoir tube, but they are not connected to it, they are connected by a short pipe to the body of the carb, where they act as a tank vent, through the air filter, or that's what I reckon anyway. Keep an eye out for it all (it's the only pipe union on the side of the carb) as the pics go on. here's a detail pic of where the 2 go into one....



The bit in the other side of the tank, opposite to the filler cap (but looks like another filler) is a simple float feed device. It works much like a ball-cock....




Now, back to the reservoir tube.
When the tap is on (which it always is now) & there's petrol in the tank, this reservoir tube will have petrol in the bottom of it (it extends well below the tank, so even if there's only a little petrol, there should still be some in this reservoir tube).
The carb has 3 pipes which go down into this tube & the ends of all 3 sit in the petrol at the bottom. Let's concentrate on the outer 2 pipes (or tubes) first (sorry, the pic is sideways) (centre pipe is removed here for clarity)....



The smaller one is connected to the crank case via the disc valve. When the piston is on it's down stroke the disc valve opens to let pressure through this pipe, but only pressure, never any suction.
Now, the bottom of this pipe does a U turn & goes into the bottom of the slightly larger one, like so (remember they are sitting in petrol at this point)....



Now, here's what the top of these 2 pipes looks like....



So, the pressure going up this smaller pipe will be forcing petrol up the larger pipe by venturi action (which I understand is all about how differences in pressure cause liquids to travel up pipes) & the petrol will come spurting out the top of the slightly larger pipe, which is L shaped at the top.

This L shape is designed to deposit the fuel onto a little shelf in the carb, which (hopefully) you can see here....



Any extra petrol will simply fall over the edge of the shelf & land back in the reservoir tube.

Once on this shelf, it just acts like a normal float chamber, the little hole in the bottom is connected to an adjustable needle jet....



Now, the other pipe which goes down into the reservoir, the centre pipe, is a primer pump tube.
This has a rod type, hand operated pump, connected via 2 ball valves & a non return valve to a union in the side of the barrel which goes to the intake ports.
It's supposed to have a bakalite handle which sits on top of the air filter, but it's long gone, so I've tapped it & found a nylock nut to fit for now, otherwise it disappears inside & I need to take the air cleaner off to get it back....



Now, one final point; the air filter has 2 erm... tracts. It has one big channel, which goes to the main carb tract, joined to the crankcase inlet manifold, flowing over the needle valve. But there's a smaller bit which goes to the main carb body, with the 3 pipes & the reservoir tube, which I think is to keep the reservoir tube & the fuel shelf thingy at atmospheric pressure. THIS is where that union is also joined to, the one which goes to the tank vent/breather tubes (or what I reckon are the tank vent tubes), this must be to stop these parts getting any vacuum from the intake or compression from the fuel delivery system pipe (not sure I've got a good pic of this bit..... Nope, I haven't. You'll have to see if you can spot it on the others), but surely the venturi action wouldn't work if the area were completely sealed? Or if it were allowed to become under pressure or vacuum?

Any questions???

OK, I've jumped about a bit there, & made a few grammatical errors, but I hope you get the gist.

I should probably also mention I've rebuilt the genny today, I was working on it until nearly midnight & I've finally got it all together. So tomorrow I will have another go with the engine, see if my pipe bending in the carb has done the trick. If it runs it'll give me a chance to test the genny.

The reason I reckon it's fuel starvation, BTW, is because when I lifted the top of the carb off, with the 3 long pipes attached, the little shelf was completely dry. This should've still had petrol on it, so I think for some reason the L shaped tube isn't depositing petrol where it should.

I've also had some trouble with the tiny pipes (on the primer pump system) splitting, so it could be something like that, or it could simply be the larger diameter, L shaped pipe getting blocked, I know it was a little furred up, & I didn't have much to clean it with.

My main trouble is my mother. She's not in a good mood just lately, so running old engines just outside the house isn't going down very well. They're off on holiday next week, & the neighbours (on that side) have already gone away (today in fact), so next week is pretty much a green light for engine mischief

Now what you've said there, in conjunction with the pictures, actually makes more sense than a pressurised tank - I never really trusted that version anyway.

Is the 'tap' mounted on the bottom of the crankcase? (You've probably already said, but I can't remember and it's too late to go through the whole thing again...) If it is then maybe it's supposed to be a drain (if you flood it or similar) and it got hooked up to the tank to try and overcome another fault causing starvation?

Some of the soldered joints on the pipes look like they've cracked - it might just be worth trying gently to re-flow them and see if they seal up and solve the issue? Wouldn't be the first time I've seen that happen.

Funnily enough I hadn't mentioned the tap yet, it is just mounted straight to the bottom of the crank case, no valves or anything else. I opened it up last night & some very oily 2 stroke mixture came out.

The float feed device inlet is protected by another screw-on filter, exactly the same as the one on the fuel tap, on the bottom of the tank....



These are made up of lots of tiny, perforated washers, & are very good filters.

My guess about the connecting piece of flexi hose is either to put the crank case fluids back into the tank, or just to put something on the end of the float feed device, maybe to stop anything getting in there, or possibly fuel was coming back out of it with the vibration of running, or during transit.

I will certainly have a go with it though, at some point today. I would also like to test the generator as well. I'm a bit concerned I may have been a bit rough with it during reassembly, which couldn't be helped. There's no may of testing separate coils now, as it's all connected back up.

Here we go, a few pics from yesterday, as the genny started to go back together....







It was too late last night to take any more, but I did finish putting the rest of it back together, including placing the voltage regulator on the back.

I'll get some more pics today.

I'm starting to wonder though, what am I going to do with my time now??? (I've already got one or two ideas up my sleeve, possibly another little project from my sister's garden )

When the engine is running there shouldn't be any crankcase fluids as such, it's just a transfer place and the oil in 2 stroke mix is mainly to lube the crank.

A lot of (better quality) 2 stroke engines had a drain in the bottom of the case, usually just a bolt. I remember on my BSA bantam that if it was being a bugger to start, I'd take out the bolt, let a load of gunk drip out and then she'd fire right up. I have seen the bolts replaced with fuel-type taps to save carrying a spanner around.

Once you've proved the alternator good or bad are you going to be doing another full-on resto on this or leaving it as-is?

Yeah, the Tarpen has 2 little bolts on the bottom of the crank case to let out any extra mixture/gunk, if it's being a pain to start, so I can't see that this engine will be much different, like you say, it's just a tap, instead of a bolt.

I wanted to strip this engine & re-paint it in olive drab, but I think we're aiming to leave it in "As Found" condition.

Our aim is to have a few pristine engines & a couple of tatty ones (the ones with a bit of character). I don't want to over-restore any of them really, I know the Tarpen is verging on the over restored, but I was careful not to over-do things.

The shiny engines will be the Tarpen & the Briggs, if we get round to doing the Douglas that will also be a pristine one, but in proper army finish, matt Khaki paint, etc.
The tatty engines will be this one & the Stuart Turner, which will be left "As Found". So we should have a nice collection, although I don't think we'll have the transport facilities to bring them all to the rallies. Maybe the very local ones we could do 2 trips & show them all.

I almost bought an old Wolseley WD2 last night, but it went over what I was willing to pay. It was missing a mag & needed complete restoration, my intention was to let my 2 nephews do most of the work, as I doubt they could break any part of a WD2. It went for a fair price, just more than I could comfortably afford. They're a heavy lump as well, & not particularly interesting, but nice nonetheless.

OK, I still can't get this thing to run properly, I've managed to get it running a bit better, but the method I used to achieve this doesn't make sense to me....

OK, basically to get this thing to run I've use a small length of gas hose to connect the crank case drain tap to the float feed device on the fuel tank.
It goes against all I think is correct for this machine but it seems to keep it running.

But, it's still not running properly, it's hunting wildly! The engine will run up to speed for a short while, then it will slow right down, almost to the point of stalling, then just as you think it's going to stop it catches back on again!

I've stripped the carb down again, completely this time. I've found what looks like a missing seal, or rather a space where there should be a seal. Where the air filter part attaches there's the big hole for the main intake, then there's a smaller hole, which connects to a half inch pipe stub, which goes to the part of the carb with the fuel shelf, pipes & fuel reservoir tube. Where the air filter goes onto the stub pipe there was no seal. I'm guessing this was supposed to be sealed. Maybe this whole chamber (the fuel reservoir tube, with all those little pipes & which is also connected to the tank breather assembly) is supposed to be under partial vacuum or partial pressure???? I just don't know.

I've made my own seal for it using bits of cork gasket material. I soaked it in oil, in the hope of getting a half decent seal, & I've put it all back together.
Once again I won't be able to test it until tomorrow, as it's too late now.

If this doesn't work then I'm out of ideas.

Hi There,
Im posting this on behalf of a guest who pmd it to myself, hope its of some use:-

I have just come across this thread by chance-Thanks for supplying so many pictures of this unique engine. So intrigued was I, that I have checked all Homelite Patents, only to find that they were not prolific in this area. The concept of an overhung crank driving a rotary disc valve is covered in one of their only two pre-war patents. I have not discovered any prior US patent covering the centrifugal throttle disc, or the very clever air-lift pump to the weir-type carburettor. This is surprising for so many unique features, and I have a hunch that it was designed in a hurry (Hence the overkill, so as to ensure that the design worked first time) and it was sent to the forces before patents could be taken out, which would have voided any retrospective applications.

Interestingly, a certain Edgar Jordan patented in 1963 (US 3262433) a model aircraft engine having the same throttle disc device, and a weir-type of carburettor (but fed by a miniature crankcase compression pump). Perhaps he was the original designer, or, if not, just someone copying this generator? Certainly, that model-engine seems to be the only patented engine resembling the Homelite.
Regarding the twin condensers, I have a parts list for the "Tiny Tim" portable generator, used on Churchill tanks, and that also has the same arrangment, so perhaps it was a way of reducing emi where required, by adding a second unit to a pre-allocated area in the flywheel magneto.
After checking hundreds of US patents relating to fuel feeds, I can confirm that there are no patents covering the use of engine compression to operate an air-lift fuel device, but many where the fuel container is at a reduced pressure, and air at a greater pressure is allowed to bubble into the bottom of the stand-pipe. The reduced density of the column then allows it to rise above the level of surrounding fluid.
I have a hunch that your troubles may originate from connecting the port from the disc valve to the base of the stand-pipe, the result being that the high pressure pulse would blow petrol back out of the pipe. Also, there would be no need for the separate small feed tank if this was the system. Is there no way that a pipe could be linked to the tapping connected to the filter (also connected to the tank vents), so allowing air to gently bubble into the bottom of the standpipe, where the fuel is at a reduced pressure?
Could the small port on the disc valve be in line with the base of the crankcase, so allowing what the Americans call the "drains" (Deposited petroil) to be automatically exhausted to the tank via a pipe connecting to the edge-filter and float valve. (The float valve would prevent this ejection system operating if the tank was tilted so as to drown the tank entry, when the gas pulses would propel fuel via the tank vents into the air-filter, flooding the engine!) The manual cock could evacuate "drains" in this case when starting.
I am probably quite wrong, but perhaps? By the way, weir-type carburettors are often preferred where there is vibration (Spring mounts) or where reliability is a prime requirement in situations where fuel may be contaminated. Anyway, thanks for your patience and fantastic photographs of such an interesting engine-'tis a pity that you use Photobucket, as I understand that they auto-delete after a time! (They seem to have just done that, but maybe my poor grasp of computer fundamentals is the reason!)

Fingers crossed,
Tandiscum.

Thanks for passing that on Paul, I'm still trying to get my head round all the information there (I've been helping my brother (Ian) with the Briggs & Stratton in the workshop, which involved some angle grinding & my ears are still ringing, so I can't even think straight at the moment)

A brief look back through the thread (it's been a while & loads of water under the bridge, so to speak) & I think things may have moved on a little bit.

It's strange though, I've been saying only today & a few times over the last week that this engine is next on my list after I complete Tarpen number 2. It's been sitting under the workbench, minus its petrol tank, for a long time now & it's about time I got it sorted once & for all.

I'll have a good read back & bring the thread up to date in the next few days.

Many thanks to Tandiscum (where have I seen that name before? ) for the message. I'll give it a good read through when my ears stop ringing (it feels like I've been night clubbing, & I haven't done that for about 5 or 6 years now!)

Hello, Matt,

Sorry to scramble your brain while you are enjoying "mechanical tinnitus"! You must be a very organised chap, as most people would find their collection had turned into "mixas", what with working with so many i.c fellas in need of T.L.C all at once? Still, your Homelite is so different that I doubt that you could find another engine on which to inadvertantly graft one of it's thrupple nuts!

I was thinking, not a wise thing to do, but perhaps your engine might work after a fashion if you left the connection to the inverted walking-stick pipe open to the atmosphere initially, possibly with a restrictor on it, just to see if fuel feeds. Of course, there would be no pressure drop across the air filter, so hence the possible need to control the air flow to the "air-lift" pump. You've probably already tried that, but I'm not sure in which chapter of your museings!

Thanks for a great series of images-I can't remember ever having come across such a novel design, and there was I thinking that Homelites could be boring, just because they keep their best bits hidden! Can't think why my moniker is familiar, unless you might have a passing interest in Military Fuze tech.? Anxiously waiting for the powders to clear your head!

Martin.

Hi Martin (AKA Tandiscum), & thanks very much for your posts. I hope now you've joined the forum you've had a little time to look around. I'm not sure if stationary engines are your thing, but it sounds to me like you've got more than a passing interest in internal combustion technology.

Also, thanks very much indeed for your tireless research into patents & suchlike, it's really interesting stuff. I have had some experience of researching U.S. patents in the past, I know just how boring it can be at times, & just how vague they can be as well. Thanks

As far as the Homelite goes, I took a picture of it tonight. It's stowed under the workbench at the moment....



Space is tight here & as it's my dad's workshop I have to be seen to make sacrifices when I want to bring another engine into it. He's now got another motorbike, so space is even tighter, so it's a juggling act between small amounts of space here & small amounts of space in my brother's garage, 15 miles away. I still manage to have several engines in bits at any one time, they seem to take up less space that way, one of my secrets is jam jars. I keep nuts & bolts off certain parts of certain engines together in separate jam jars. I find I don't have to label them, as there's usually enough clues as to where they belong just by looking at the contents.

To bring the thread up to date:-
Basically, I made a discovery when it was last running, I found that the fuel tank was peppered with tiny holes on it's roof, here's a few pics of what I found....













I even managed to get a few pics of the inside, the worst bits are the top of the tank....





I decided it was too much to solder, although I've soldered what I can. What it needs is a fuel tank sealer, but these are no good on their own, first it needs treating with a special de-greaser & de-glazer to remove the years of oil & petrol residue, then it needs treating with a rust eater solution. Then it needs inspecting (by me, nothing too technical) as many of the holes are likely to open up, any larger holes (over 2mm) will need externally patching, then, when it's completely dry (& I'm talking about a possible week, or two, long drying process) it needs treating with the tank sealer.

I've done a little research into this, & it seems the American tank sealers are best, as the recent addition of Ethanol into UK fuels has started to degrade many of the UK sealers, the Yanks have had Ethanol in their fuels for well over a decade now, so their sealers are best able to deal with such chemicals.

The tank sealer & associated cleaning & preparation chemicals are available as a kit, but the cheapest of these is just over forty quid. Which, up 'til now, has been an amount I just can't afford to splash out. But, as I've recently sold an engine, & have another on the market, I suppose I should get the kit & start the process, after all it's a process which is likely to take at least 4 to 6 weeks (possibly longer) until the tank's ready for use again, so the sooner I get on with it the better & I can fit it in around my other projects, as there's a huge amount of that time which is just waiting time (my favourite excuse "materials hardening" ).

I have looked into getting a manual for this generating set, & I thought I had found one, in America, I paid for it but soon got a refund with the message that they "couldn't find it", I was absolutely livid! But I bought another supposedly helpful American book called "Intertec Small Air-Cooled Engines, service manual * 16th edition". this contains much information about similarly designed Homelite units, but only has details about the later carb & only really tells me what I already know from my own research & what I've found out by dismantling this engine. It also states that this fuel tank is "Pressurised by crank-case pressure", which just doesn't ring true to me.

Everything I have done with this engine, all the metal pipe connections, are as they should be & as they are on other models. I've even spoken to an Australian enthusiast on SmokStak forum who has (or rather had) a couple of these engines, one was a complete generator, similar to my one with an identical power plant, which had never been started before he got it & was in fantastic original condition. All his pipe connections were much the same as mine, & he confirmed to me that there should be no connection between the crank case drain tap & the fuel tank. But his didn't have the extra fuel float feed device, so my guess is the tank does need to be sealed from atmosphere & a length of rubber hose from the float feed device to the closed crank case drain tap is enough to achieve this.

But who knows for sure? I bet someone does, but they're not talking to me! Anyway, this is unlikely to be under test again for some time, even if I get the tank sealer kit tomorrow (which aint gona happen) it would still be at least 4 weeks before I could even consider putting fuel in the freshly treated tank.

Be sure to keep an eye out though, as this will be the first place I come to when it's back together again. I'm also happy to discuss any other thoughts or questions or information about this engine on this thread, by all means keep it coming.

Right, I went mad last night & ordered the fuel tank sealing kit from eBay. I had a little "engine fund" money left over from the sale of the JAP, & as it looks like a new barrel for my Stuart Turner P6 isn't forthcoming I thought I should be getting on with something else. The Homelite caught my eye as I was putting everything to bed last night, so I guess that set the wheels in motion, in my mind, & at around 11:30pm, sitting in bed with the lap-top, I finally pressed the "Buy it Now" button.

the kit consists of a special de-greaser, the special rust eater & the tank sealer, it also comes with a patch-up kit for any larger holes (consisting of a brush & a piece of cloth patch, to be used with the sealer compound if needed). So this should be perfect for my needs.

However, this is not a quick process by any means. I've researched this quite a lot, & tank sealing is not a job to be taken lightly, if you want it to work you need to take your time, use all the right bits & pieces & do the job very thoroughly & very carefully. It is likely to be at least a month, if not 6 to 8 weeks (from starting the job) before the tank will be ready for fuel. They say it can be done quicker, but I've learnt that if you want it to last, you need to take your time & let the stuff go off properly.
This cold weather won't help either, hope my mum won't mind petrol tanks hanging from her ceilings over the christmas period .

For those who are interested I will probably do a separate write-up on tank sealing & put it in the relevant section (perhaps "Workshop" or somewhere like that). I have a few tanks to do, as I'm told there's always some left over & this stuff can't be stored after opening (it's shit or bust, so everything's gotta be right!) so I will be doing every tank which needs doing at the same time.

Fingers crossed indeed.

P.S. here's the kit I've bought....

http://www.ebay.co.uk/itm/160868435314?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Nuts I was the same when I sealed my WD8 tank, when I finished doing that tank I poured the liquid into a nother tank and sealed that one as well not to waste it.

Stu.

stationary stu wrote:Nuts I was the same when I sealed my WD8 tank, when I finished doing that tank I poured the liquid into a nother tank and sealed that one as well not to waste it.

Stu.

Think I've got about 5 tanks & some old petrol cans lined up! Doubt I will do them all, but I will order them by preference & see how far I get.

No problem reusing it Matt, I have been using that stuff for years on all my tank's and as long as you pour the excess back into the tin and reseal it you can use it again..and again! Be warned that if you spill any and put the tin onto the spilled area the tin will be stuck solid in a couple of hours, I did that and ended up ripping the chipboard work service trying to extract the tin! I used a hot air gun to dry the tank thoroughly after the cleaning process, and then left it on the radiator for a couple of days and then away you go, get pouring but make sure that you wipe clean the threaded drain and filler outlets before it sets. This is the reason why whenever I start a restoration the tank is the first thing sealed and then painted to make certain that it has maximum drying time.

Pete.

The stuff I have they say you can put it back in the bottle but I thought it would be dirty so just used it up. I sttod my on the radiator and after every 24 hours I moved it round to get all the tank coated and it sure did a good job.

Stu.

Foden wrote:No problem reusing it Matt, I have been using that stuff for years on all my tank's and as long as you pour the excess back into the tin and reseal it you can use it again..and again!
Pete.

Have you used this same stuff then? I thought this one said you have to use it all up & you shouldn't put the lid back on the tin???

I know some of them say you can use it again & again, maybe I have got mixed up with some other brand (I've looked at so many). I was going to at least try & save it anyway, just because it's so expensive, but I will be happy if I can store what's left for future use.

Also, the instructions I read said you need to patch any big holes first before coating the tank. But then it said you couldn't re-seal the tin, which didn't make sense to me, as you'd have to wait for the patching to go off before you could start coating the tank anyway. I hope I can save it, as I will probably need some in the future. I'm also planning on saving & re-using the preparation chemicals, as they are also very expensive to buy on their own. The rust-eater could come in very handy.

It's been dispatched this morning anyway, so should be here by the end of the week, so I can get started. Wish I'd done this a week or 2 ago, my mum & dad were away last weekend, would've been a perfect time to fill the house with petrol tanks.

Yep, same stuff. Ignore what it says on the tin, they are selling it! Never had a problem reusing it, but you do need to reseal it before it starts setting. Oh, and wipe the outside of the tank clean as it doesn't take paint well.

Pete.