Col B

My Feedback: (3)

I have read a number of posts regarding idle down problems with some of these engines. The posts I have read suggested this problem was due to air leakage around the needle valves.

Having just purchased this engine used on RCU I was aware of the potential for this problem and sure enough on the maiden flight I experienced an RPM hang up at about 3500.

I contacted CACTUS AVIATION and discribed the issue to Bobby Wilson pointing out what I had read. Turned out that this problem is not a carb issue but rather an ignition issue related to the spacing of the two hall sensor magnets. These early production models came out of the factory with the spacing too far apart. Thanks to Bobby, he saved me a lot of time an effort chasing this down the wrong rabbit hole.

I sent the engine to CACTUS to have the magnet spacing adjusted and while at his shop he cleaned it up, repainted the head and adjusted the magnets for a great price.

I'll try to post a follow up when I get the engine back and running.

Col B

Ram Jet

I'd like to see it. I'm glad you found a skilled, reliable wrench.

Bill

Tired Old Man

My Feedback: (1)

Nice to hear about the service.

EddieDean

My Feedback: (3)

I also have a 3W-80xi CS that may be suffering from the same problem. When I go from WOT to idle the engine comes down to about 3500 rpm and then slowly (very slowly) comes on down to the correct idle. Very interested in hearing if this fixes the problem.

Col B

My Feedback: (3)

Eddie,
I believe this was a problem with all early production engines. You might want to call CACTUS and give Bobby your serial number. He can tell you the production year and may be able to find out if your engine was one of those produced with the magnet problem.

Bobby ran the engine after he reset the magnets and told me it was running great now. I'll let you know as soon as I get it back on the Aeroworks Extra.
Col B

EddieDean

My Feedback: (3)

Thanks Col B. I'll be waiting to hear the results. My 3W80 is on a Wild Hare Extra 260.

flatspinjim

My Feedback: (3)

EddieDean What was your all up weight with the 80? I have the Wildhare 260 with a DL 100. Mine came in at 27.9.

EddieDean

My Feedback: (3)

flatspinjim,

I finished my WildHare Extra 260 early last fall and if I remember correctly it was about 22-23 pounds. I have the 33% Extra with 98in wingspan and it sounds as if you have a 35%.

Eddie Dean

Col B

My Feedback: (3)

EddieDean,
Just wanted to let you know the engine idle down problem is now solved.

Throttle inputs were precise both increasing and decreasing RPM....no more issues with waiting for the idle to drop down during final.

I shot about 5 low approaches, 10 touch and go's and a couple of long drug in finals and was able to control the power with no RPM delay's or hang up's.

The guy who sold it to me told me I was messing up the carb needle settings but he obviously did not know about the magnet issue with these early production series. Bobby moved the #2 magnet about 4mm closer to #1.

r,
Col B

EddieDean

My Feedback: (3)

Col B,

Glad to hear of the good results. This engine has been out for a while, strange no one else is reporting a problem. I have a 3W50i that is doing the same thing and it has two magnets as well. After the holidays are over I'll have to see if I can get them fixed.

Happy New year
EddieDean

SRimer

I have a brand new 80xi, does this issue applies to 80xi also?

rcdude7

My Feedback: (264)

I do also, what should the spacing be between the two hub magnets??

Col B

My Feedback: (3)

I believe this problem was solved shortly after the initial production run however, I do not know the date of mfr or serial numbers of those engines with the magnets not configured properly. I would think a new engine would not have the same problem however, you can contact either Bobby at Cactus Aviation or Gerhard at Aviation International and they would be able to help you.

My engine came off the factory line in 2006 and the idle down problem was quite significant. If your engine has this problem you would know because the idle will hang up at 3-35K and remain there for about 10 seconds before falling off. Of course, this really presents a problem when landing because every time you advance the throttle to maintain your rate of descent it hangs back up again.

I'll try to post a picture of the magnet placement later today.

Col B

j39j54

Col B
All problem solved by doing this?

Best regards
Oak

Col B

My Feedback: (3)

Roger...problem solved.
Col B

EddieDean

My Feedback: (3)

I've sent my 3W80XI-CS to Gerhard at Aviation International. He knew about the problem and said he could fix it. He didn't say ( I failed to ask) what it would cost, but I'm hoping 3W will pay for fixing the problem. I wouldn't mind paying the shipping. I think that would be fair.

Will post how it runs when I get it back and installed and the weather gets better.

Eddie

Col B

My Feedback: (3)

EddieDean,
Gerhard was the one who told me about the magnet placement probem so I'm sure he will be able to make the adjustment. I sent my engine to Bobby Wilson at Cactus Avaition for some other reasons and he did some additional work as well like decarbon and change the rings. I've also determined that setting the Tillotson carb properly...to both the atmospheric conditions and prop dynamics...are other key parts of the equation which you have probably already figured out.

I'm using a high quality synthetic oil at 80:1 and experimenting with several props to include a Vess 26 A and B and MSC 26-10. I have a Bambulla 26-10 on the way. The MSC provides the best throttle response downward and I believe primarily due to the weight and blade width. I have the L needle at 1 1/8 open and the H just at 7/8 turn. IMO setting the L properly is the key to establishing the best throttle response downward. I'm also using the side discharge exhaust...a little louder but noise is not an issue where I fly.

I would be interested in knowing your set up as well.


Thanks,
Col B

EddieDean

My Feedback: (3)

Got my 3W-80XI CS back from Aircraft International in January but only got it mounted in my plane last week. Moving the magnet has solved the idle down problem. Gerhard also cleaned the carbon from the piston and cylinder wall. While he had the engine he called to say the engine wasn't putting out full power and the ignition was defected. He replaced it under warranty. I was pleased with both the service and turn around.

However, I now have an engine that will not go above 4600 RPM at WOT.It was turning almost 6000 before I sent it off to be repaired.I'm running a PT Model carbon fiber 26 x 10 propeller and a Pitts wrap around muffler (can't find aname on it). Gerhard suggested that the muffler or prop was the problem but this is the same prop and muffler I was using before the repair. I removed the muffler and tried a wooden prop without much difference. Logic would say that if Gerhard found the ignitionto be theproblem (of not putting out full power) then this ignition isalso bador the ignition was never the problem. I suppose I could send the engine back again but as I was removing the new ignition from the firewall box I noticed one end of the plastic back plate is broken. It was mounted with rubber grommets so don't know why it is broken. Didn't notice it before I mounted it. So if the ignition is the problem, guess I'm out the cost of a new ignition. I have a 3W-50i that blows fuel out the carb and soaks my plane with raw fuel. It has the same ignition. I plan on trying it tomorrow.

jkhorvath

My Feedback: (1)

I also had idle issues with my 3W 80xi until I replaced the ignition with one from CH Ignitions. Pretty simple installation since the pickup fits neatly into the 3W plastic pickup mount (although please remember to epoxy the new sensor into the 3W plastic mount). After re-timing the engine at 26 to 27 degrees BTC (and tweaking the low end needle just a bit richer), it runs much better, I have a much more stable idle, I have a bit more low-end throttle response, and it is a world of difference easier to start. It starts now after one or two flips (warm).

Col B

My Feedback: (3)

EddieDean,
Ihave a CH ignition to fit your engine if you are interested I'll sell it to you for $50 plus shipping. It's set up for the 80xiCS and very easy to install. Let m know if you are interested.
Col B

EddieDean

My Feedback: (3)

Col B.

I'm interested in the CH ignition. So it will work O.K. even though the 80Xi has two magnets?

How do you want to complete the deal?

EddieDean

Col B

My Feedback: (3)

EddieDean,
Yes, the CH ignition simply ignores the negative polarity magnet (the first one that moves under the sensor) and sends the ignition signal based upon the positive polarity magnet.. It's simple to set up but you will need to attach the paper protractor to the front of the hub and set up a fixed pointer that points to zero degrees when the piston is at top dead center. There should be a mark on the engine and hub thatwhen aligned, setsup the piston at TDC. You will then remove the plug, connect the spark plug to the ignition, ground the plug and set up the sensor so the plug fires at 26 degrees before top dead center. Make sure to rotate the hub in theproper direction CCW, when setting the hall sensor position. I recommend removing the 3W sensor and using the CH stainless strap with sensor attached. It's already glued in place and ready to install.

Send me a check or money order to:
Greg Brown
4236 Cougar Circle
Niceville, FL
32578

Make it for $55 and Iwill cover any additionalshipping.

EddieDean

My Feedback: (3)

Col B., The weather here has been very wet and I haven't had a chance to try the ignition from my 3W-50i on the 3W-80Xi CS as yet. Maybe tomorrowor Saturday. I'm leaving for Hawaii on Sunday and will be gone a week. If you don't mind I'll wait untill I get back to let you know if I need the CH unit. The price seems fair. Thanks so much.

Eddie

Col B

My Feedback: (3)

Eddie,
No problem...let me know when you get back. Have a safe trip.

EddieDean

My Feedback: (3)

Well, I have tried two propellers (one carbonfiber and one wood), two electronic ignitions, new fuel and checked the carburtor and reed values and still can not get more than 4700 rpm out of my 3W-80Xi CS. I'd swear I got 6700 before I sent it in to have the timing magnet moved. Hope to have time today to check the timing. I've bought a new spark plug and will try that as well.

At the moment, Bob, I guess I don't need to purchase another ignition. Thanks for the offer.


BTW, Hawaii was very nice but I never heard a model engine the entire time I was there.

Eddie