DKjens

My Feedback: (50)

I picked up a Herbrandson 280 some months ago. The engine has been converted from the original dual carburetor, piston ported intake, to a single Walbro 6-peetal reed valve intake, in line with a DA150. Engine is using the older style 3W ignition. I found out the ignition was bad, so I bought a new. When first attempting to start the engine, I was unsuccessful, because I wasn't getting the engine wet enough. After choking the crap out of the engine, it fired right up. After initial two flights, I got hold of another prop, but now, the following weekend, the engine would not fire at all. I sent the new ignition back to be checked, and it was fine. The engine still would not fire. I tryed new spark plugs, still nothing. I get frustrated, and send the engine to Ralph Cunningham. I explain the situation to him, and ask if he can strap it up and get it running well. Ralph has the engine for 4-6 weeks, he checks it out and is very impressed with the machining etc. but never gets around strapping it up and run it, and does not sound like he is going to. I et impatient and have Ralph return the engine to me. I strap it up at home, and it started this Sunday. I ran it for 1-2 minutes, then shut it down, to go get a rope to tied the stand down better (the stand is a picnic table, and I was sitting on it, or it would have taken flight). Well, that was that, now the engine won't even cough. I have choked the snot out of it, oz'es of gas running out of the carb, nothing. I tryed a DA ignition, nothing. Why the heck will it run one minute, then be as dead as a doornail the next? I am going to see if I can locate a Miller started, then mount a race prop and my aluminum spinner, and crank it with the starter, but it really should start by hand. I am desperately looking for suggestions, please help.
DKjens

DERF-54

My Feedback: (48)

Have you tried to start it with the choke on? What are your low end needle settings? Did you pull the carb to check the reeds? I have fixed up a couple 3W's that had this problem and it was do to the reeds not sealing.
I have also seen this problem with a Zenoah G-62, it turned out to be that the low end was just to lean, it would fire when choked but as soon as you removed the choke it would not do a thing, this was after a good flight.
Give me a bit more info.
Derf

w8ye

My Feedback: (16)

Are you getting a spark to your plugs?

DKjens

My Feedback: (50)

Derf,
When I had problems with the engine when first getting it, I pulled the carb. and reeds, and checked 1. That they would open (weren't stuck) and 2. that they closed and sealed well. Both was a posetive. The carb is about L:1.25 - H:1 or there abouts. When the engine has run, it has seemed to be rich on the bottom, as in loading up quite a bit when taxiing out, and it taking some time to clear out. I have also tried cranking the engine with the choke on, still nothing.

w8ye,
The spark on these small cm-6 plugs is hard to see, but it's there. I've had the plugs out and cranking, and I get a spark. I have checked the gaps, and they are about .018 - .020 I believe, but anyway the size I've read here that they should be on a 3W.

I do think it's a fuel problem, maybe, because even after chocking for a long time and pulling a plug, there is only a faint smell of gas, where I'd think it at least would be wet or most, but it's dry. Another factor is, that these plugs are mounted in a brass insert, which is a little longer than the plugs, and thereby shadowing the electrode a bit. I am wondering if this has an effect, but I would think it would still fire.

DKjens

Crusty

I wouldnt call the spark on a cm6 hard to see, mine is a quite obvious fat blue.
When you say, you have tried different ignitions, was this a complete swap out or did you use the same sensor, magnet or ht coil?
EDIT... of course that would not explain a dry plug when the carb is dripping..............if your reeds operate correctly and you got enough compression to draw fuel choked then it should get wet ifits not firing[sm=spinnyeyes.gif]

Antique

My Feedback: (4)

The way the ignition is set up on your engine makes it almost impossible to check the timing..The ignition takes a good flip to make it fire..It will take a really good starter to crank it fast....Only way I can check the timing on a shielded ignition system is by using an old 3w ignition system with part of the shielding removed on one of the wires, so an inductive timing light can be used...If the little rotor has slipped out of position on the back of the crank the engine will never run.....

DKjens

My Feedback: (50)

Crusty,
To be honest, I am suspecting the pick up, which is mounted on the back plate, with a small magnet on a disk on the rear of the crank, but since I'm not getting a wet spark plug there are probably other issues. I figure that if I try and crank it with a starter, it should draw fuel really well, and either start and run, or get wet plugs.
What did you decide to do with your inserts, I suspect we have much the same problem there. I feel the electrode is shielded a bit from the air/fuel mixture, but I still think it should get wet.
I am used to operate DA150 engines, and they fricking start and run in just a few flips. I would be willing to just send this engine to somebody, which I did and nothing was done, and have it fixed, but I don't know who.

Ralph,
I guess I will remove the back plate and see if that plate is loose, or could somehow have moved. What kind of signal is generated by the pick up and is it something I can measure with a multimeter to check that it is giving a signal?

DKjens

Antique

My Feedback: (4)

It's not a Hall sensor, so it takes a little more speed to induce enough current..Only two to of the wires connect to the ignition...Maybe Dave or Brian at DA could shed some light on the ignition, I have no idea....

DKjens

My Feedback: (50)

Well, just ordered a Miller Gear Reduction drive for my Dynatron starter, heck, what's $116.00 in this hobby anyways? If it works, it works, and I'll just have to start it with that starter at the field as well.
DKjens

Crusty

DKjens,
Re the inserts, I took a look today and found I could only remove material from the end nearest the piston (there is a sealing shoulder on the outer end), which would not help me get the plug any deeper in the combustion chamber, I tried removing the insert and fitting a bpmr7 but the piston hits electrode, maybe a standard thread short reach will fit or a extra washer under the bpmr7, but then as RCIGN has pointed out id have to modify/change my plug cap shield.

mglavin

My Feedback: (31)

Pull the plugs and connect the sparkplugs. Cycle the ignition switch on and off quickly. If the capacitive discharge side of the module is functioning you should see some spark.

3W ignitions use a pickup coil and a magnet in the hub to generate an inductive spike which in turn triggers the ignition module to unload stored energy of the coils/capacitive discharge circuit.

Typically failures are the pickup coil and or the magnet in the hub is weakened from heat. In either case the output side of the ignition is not triggered.

I’d use a 6.0V power supply. Verify the electrical connections, switches and connectors are sound. Loose, high resistance and or poor connections are problematic.

Antique

My Feedback: (4)

...Take the steel cover off the carb and if the diaphragm is not really flexible it won't let the inlet needle open....I don't remember if I checked it.. The cylinders have been extensively ported for racing but if it ran before it should run now...

DKjens

My Feedback: (50)

I had the carb and reeds off tonight. With the engine upside down on the bench, I could see fuel in the case, so some fuel did get in the case. I took the rear cover off and advanced the pick up, or rather magnet, it looked like it was timed slightly after TDC, I timed it as close to TDC as I could. Re-mounted the engine and tried, nothing. With the plugs out and in the cap, on the cylinder, and cycling the power, I do get a spark. I suppose I should go out now that it's dark and check for a spark when flipping. Funny thing though, no matter how much I choke it, pull a plug, it is not wet, just the faint smell of gas, and I would expect it to be soaked.
I just went out to check for spark in the dark, and I am very happy to report that I get good spark when flipping, on both plugs. I will pull cover off carb tomorrow and check diaphragm for stiffness or sign of any debris. Makes me feel good, I was fearing the pick-up was bad, but looks to work fine.
DKjens

GoeKeli

My Feedback: (18)

Hi Jens, fuel delivery might be it. Did you check the diaphram? Is the pressure pulse hole lined up with the carb? Sounds really frustrating. If you need some help I will be around this weekend. Can you put some fuel in the jugs with the plugs out and get it to pop? If so, you know whats up. Coil pickup? WOuld it be easy to convert to hall sensor? I would call Dave ASAP!

Joe

mglavin

My Feedback: (31)

You cannot convert a DA/3W ignition system to utilize a Hall Effect Sensor.....

Antique

My Feedback: (4)

You could take the back cover off the carb with it still mounted on the engine and see if the pulse is getting to the inside of the carb, the WB Walbro carbs pump like crazy with a pulse..
Some of the mounting holes on the back of the case go all the way through, if any one of them is leaking your pulse is going nowhere.....

DKjens

My Feedback: (50)

I had the front cover off, the diaphragm was nice and soft and plyable, the arm did require a bit of pressure to open the needle, there was plenty of fuel. I know the carb pumps good, when choking there is fuel all over the place. I took the spark plugs out, filled the jugs with fuel, spark plugs back in, still wouldn't start, not a poop. So here is what I know:
1. The engine ran well last Sunday, however have been unable to restart engine after first run.
2. Checked for spark on both plugs at night, check, so ignition and pick-up work.
3. Ignition is getting 6.0V from a 2400mAh Li-Ion and regulator.
4. Carburetor is pumping well, both needles open 1-2 turns at different attempts.
5. Good compression, I tried with a 22x27 prop and it was almost impossible to flip, went back to 36" prop.

I will now just wait for my Miller Reduction drive and hope that will turn this engine over and I'll get it started, and just see what happens after that.

Ralph,
This is why I was trying to push you to run this engine, but it didn't sound like you were ever going to mount and run it, so I got impatient. It's all fine that the engine and machining is a piece of art, and in theory it should put out alot of power, but this problem is really aggravating, and I would very much like to get it resolved.

DKjens

Crusty

wow no pop with fuel in the jugs eh?,
When you say you have to wait till dark to see a spark, is this with plugs out of jugs and you getting a faster flip than when they are plugged up?. Its looking like you either cant crank it fast enough to get a half decent spark or your timing is ver-very retarded.

Antique

My Feedback: (4)

Not TOO busy, this is a part of the backlog

DKjens

My Feedback: (50)

Well, I wanted to post an update - I got the engine to run. A good friend suggested mounting the engine upside down and try to start it that way. It made sense to me, because although I knew that the carburetor drew alot of fuel, the reed valve intake block is quite large, and there may be a problem getting the fuel from the carburetor all the way into the case. So, I mounted it inverted in my stand, and it fired up. It was belching smoke and shaking like a mo-fo, but that is very likely from me messing with the timing, closing the gap on the plogs, and having the L needle 2 - 2.5 turns out. I have reset the timing which, after talking to somebody at AI, appears to have been fine to begin with (I had advanced it slightly). I will turn the cylinders and pistons 180 degree, so that the intake will be on top of the engine, and the exhaust will still be out the bottom. Since engine is then, after tuning on the stand, going back into the Yak, which has a big round cowl, that will work just fine, and choking the engine will be easier. I called and spoke to Dean Herbrandson, and received confirmation, that turning the cylinders and pistons as described, is just fine.

So, now with reliable starts and running to look forward to, I can't hardly wait to fly this 40% Yak with this engine, swinging a 36x11 prop close to or at 6000 rpm he he, it should not be lacking in power.

Last update. Took the cylinders and pistons off and turned them 180 degrees, so basically with the engine (crank case) upside down, the exhaust is again at the bottom, and the carburetor is at the top. Also adjusted the timing to where it looked like it was before. Mounted engine, mufflers (cans) and prop and it started right up. It was shaking a bit, but from running rich. I could now get to the needles while the engine was running and I leaned the L first. I was running out of fuel, so I stopped it. I refueled and after re-choking, the engine started up again. I kept turning the L in until I got smoother running, decent idle and good transition right off idle. I goosed it and leaned the H needle as well. I don't know how fast it turns, but it's bloody frightening sitting right behind it while at WOT. I will now remove DA150 from Yak, and install Herbrandson280 he he.

DKjens

Mad Mat

My Feedback: (2)

Hey Mate, nice to hears its running, and I thought that you Danish have no feel for engines.....

And, make sure you tie the table down real well, that big boy could take out the side of your house......

I tell ya, its one big #%@#$%@@#$@#$ of an engine, thats for sure.





MM

Crusty

Nice blanket statement on a whole nation, Matt

Mad Mat

My Feedback: (2)

RE: Crusty,

Not a blanket statement on a whole nation, just a light hearted reminder to a good friend that he hasn't come down drinking lately. Besides, you should hear what he has to say about us Aussies and our kangaroos............. Ever since an Aussie girl married a Danish Prince, things just haven’t been the same.......

Apologies if you saw it in any other light, it was not the intention.


MM

DKjens

My Feedback: (50)

*** Mad Mat, I thought for sure you had worked your way to a stroke by now he he. What happened to the month your Sheila supposedly were "out of town" and you were going to let oose a little he he.

Actually, this engine had both a fuel draw problem, which I've solved per previous posts, but it also had a ignition timing pick up problem. The magnet was positioned in a way so it travelled at to small of a circle, and the sensor coil was positioned so the distance to the magnet could not be adjusted. So made for a sporatic spark when flipping the engine to start it. Sure, I had this asian guy suggest that I flip it faster, I asked if he felt like giving it a try. The first attempt he didn't even get it through compression, the second he did, and he ran out of seam he he. Anyway, I've modified and mounted one of the pick ups from a DA150 on the front of the engine, and I got a magnet from DA which I mounted n the hub, travelling in a circle diameter of 2.4". I now have great spark and am looking forward to flying this some more.

Mat, I plan to be at WN Saturday in the am, I have a linch to go to , so is leaving around 11:30. I plan to be at Sepulveda Basin Sunday, se what you can do about it mate. Oh, and now we're going to have a bloody cross between a viking and an aboriginee/kiwi be the next royalty in little Denmark.

DKjens

Crusty

Matt, its me that should apologise, I should recognise a bit of banter by now
and with feet like I have, I could do without one of them in my mouth, but I never seem to learn...sorry