RCU Forums - 3w100 HELP!!!

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I have a bout 65 flights on my 100. Last night on the last flight it was running very rough for the first min. or two. Then it was fine.

Today It started the same way but didn't clear up, landed. I leaned out the bottom end just a bit(less than 1/16 turn) and went back up. Not much better, then it just Quit.

Now It just runs for a split second then stops. I opened up the carb. and cleaned it out, still the same.

Temp is 185 to 195. cowl is baffled. running mid grade gas with Honda hp2 50:1 3w 26-10 turned 6700 rpm.

Please help!! thanks Scott

Ignition plug caps

Your problem is probably a bad ignition plug cap. 3W had a bad supplier for these a year or so ago and they eventually go bad. I had the same problem with my 3W-78 twin. It actually kept dropping a cylinder and it would run rough and not accelerate. You may want to start here with the trouble-shooting.
Good Luck, Travis

Had the same trouble with my 3W100. Changed my ignition to DA ignition and no more problems.

I have a 140 not in use right now, can I use that one?

Scott

Yep, its the same ignition. That will be a quick trouble-shoot to tell you if it is your ignition or you need to look elsewhere. I would bet though that swapping the ignition will solve your problem.

I put the other ignition on and it runs a lot better. Thanks to all who helped.

Thanks Scott

ive been having a problem where when i go into a hover.. or vert it either deadsticks, or is just about to until i flatten out.. ive redid the fuel system etc.. could the plug thing be a problem maybe?

Quote:

Originally posted by Lonestarxp
ive been having a problem where when i go into a hover.. or vert it either deadsticks, or is just about to until i flatten out.. ive redid the fuel system etc.. could the plug thing be a problem maybe?

At what throttle position are you at when it dies? You might be set too lean. Try a richer setting.

I can just about gaurantee you that it's the IGN or the caps. A fix is to put a C&H on it, or like Foxbat suggested, dump it, and get a DA. I had an 80 do the the same thing some time ago. Had to resurface the carb block, straighten the crank, replace the caps, and finally replaced the IGN. I then sold it...got tired of messing with it. All engines have some troubles I know, but not all of them have the same troubles over and over except for these 3w's. I've seen it over and over, and before somebody thinks about flaming me, I've helped the guys fix these problems at the field *many* times, so any flames would be meaningless. Just stating the facts...

A bad bunch of NGK CM6 plugs got out too. The porcelain seal leaks and you will find a brown ring of burnt oil on the outside of the plug where the porcelain meets the metal shell of the body.
I would get a new set of plugs and gap at 0.015". My 3W-100 still runs strong and as reliable as a clock after more than 600 flights. Original 3W ignition, DA ignition caps.

my throttle position is about little under half.. i do belive.. it's been last summer since i tried.. ive messed witht he needlked with about 4 other gient scale flyers at my field... no luck.. in fact one of the guys who is very exspeienced asked if he could perform the hover to see exactly what happens.. and the engine shut off, then he didn't make it on a dead stick landing.. had to fix the underside.. and he bought me a new prop =/ so instead of testing her in the air im gonna have a few guys hold it up and do a "controlled" hover =) if tubneing can't work, ill look into another ing.

Oh, BTW. i did get new plugs before it started doing it.. yes there the right plugs.. but whats this about gaping? am i supposed to do something to the plugs before i put them on? just checking..

-John

Another symptom these engines are notorious for, is 'coughing' in a hover...when they do it, I think you know the results. Do NOT test this engine in a hover...you will very likely end up losing a plane. I've said it once gently, but I'll go out on a limb and say it again a little more strongly, but with one exception...if these '3w's' are acting right, they are ok, but when they are not..............well, you've already seen what will happen....that's not a fluke...it happens all the time. I've *GOT* to be straightforward here...that does does not happen with a DA. It takes literally a catastraophic failure to bring one of those engines down. I have NEVER had that happen, and have NEVER seen it happen. I have seen it happen time and time again with the the '3w's' because of leaks, case problems, crank problems, IGN problems, carb problems, tolerance issues, and cap problems...they have serious QC issues at 3w...issues they did not use to have in the early years of the TOC...I do not undertand this given their past reputation, but it's appearant, that they are not doing the same things they used to. I have seen pics of engine cases literally thrown into parts bins....that is not the way to take care of a case...especailly a cast case that is prone to leaks to begin with, I have seen cranks also thrown into bins...it makes one wonder how they become so warped. Bearing life? well when the crank is shown out of runout, it's no wonder the bearings fail! I have personally been to the field and proven that 2...not 1, but 2 3w 200 cases had holes in the cases and were leaking causing havoc with the engines...were they lean? hell yes they were lean! and it ruined the engines...they had to be sent back, and the pilots lost valubale flight time...damn near sponsored pilots I might add. This is nothing new... this is what I have seen OVER and OVER again. I have nothing against 3w. I have nothing against Germany or the folks who manufacture these engines...but if they are are gonna charge a premium price for these engines...one that is more than the competitions, they need to get a grasp on QC. Modellers pay pay a pemium price for those engines...more than any other...they should not be having to rebuild a brand new engine!!! Think about it... are you getting your moneys worth? I don't think so...I keep flying while I work on a few of my freinds engines at the field...guess what? They're about ready to dump them too. These guys in the SE want to fly...they don't want to be grounded working on a engine that won't run. That's just reality! Flame me if you want...but that is reality.

WELL SAID, flyin-hot, and in a much nicer way than I would have stated it. :)

EVERY 3W I've owned has had the exact same problem at one time or another. . Either the carb block warps (or cracks in the case of the "Newer design"), the case starts leaking at a seam, you lose a seal in the front bearing, or the ignition starts breaking down causing misfireson one cylinder. And YES, the porosity problems are rampant with 3W motors because the crankcases are cast, not CNC machined. All in all it's a very SLOPPY and badly manufactured product that people just insist in still using.

I've lost 3 airframes (expensive ones) due to 3W's "Coughing", misfiring, or just shutting off at the wrong time. I used to have 6 at one time, now I have three because I sold the others, and one of THOSE is a 240. . never run. The two engines I have on my big planes are a 150 (new style) and an old 140TOC that has been gone through and has all the little problems fixed (DA carb block AND ignition on both motors)

That being said, I'm buying BME's (three received/on order, had 3 others a long time ago. . . wonder why I EVER switched) and have a DA150 just waiting for it's ride to be finished. NONE of my BME's or DA's have ever hiccuped, misfired, or deadsticked due to a mechanical problem (running out of gas or ignition voltage does not count :) ). I think that just about says it all.

Nothing wrong with a casting!
All castings will have some porosity, but if done right the porosity will be controlled so that the parts don't leak air. All those GP 2-stroke motorcycles use cast engine parts including crankcase and cylinders. All our engines (including DA, BME, ZDZ, Zenoah, 3W, Brison etc.) use cast cylinders. If castings were all leaky, then all these cylinders would also leak air.

I'm not saying you guys aren't seeing leaking cases on 3W. I'm saying there is no reason a cast crankcase won't be every bit as good as as one machined from billet. It's all a matter of design, quality, workmanship, and alloy choice.

Gee. . Diablo said it perfectly. . its a matter of design, QUALITY, WORKMANSHIP, and alloy of choice. As you can see, the two things that most people complain about with 3W's are listed right there. . . . Quality and Workmanship.

Kind of speaks for itself.

Hello, I started this thread a long time ago. I just needed an answer to my question. I don't like bashers. I know you think you have a valid point, and you may. This is not the reason i started this. So please take it some where else.

Thanks, Scott

Sorry, Rcflyguy_26, we were addressing Lonestarxp's problem with his engine deadsticking with alarming regularity. Seems it happens way too often to a lot of people, and a few of us are upset with it.

lonestarxp, Do you have a temp Gage? one of the inferred ones? you need to check the temps. I found that the carb is getting too hot, Simply cut the scale carb opening in the front of the cowl. this will let air in around the carb and cool it off. Gas goes to vapor at a round 120 deg I took a carb temp last year at 105 deg in October. I started asking around. All the TOC guys have the fronts cut out of the cowls. In short the readings are 10-20 deg above the outside temp. Once we start flying around here again I'll post some temp readings. The cylinders can handle higher temps (250, 300+ not recommended) As long as it's not lean. Too lean will do one in in a hurry. I try to keep mine around 180-200deg. If you want pics of my set up let me know.

As for the 3W vs DA thing, Lets just help with the problem. O.K. guys?

Later, Scott

yep, sure do have a temp gauge.. i get temps around 220-230 on the heads.. have nt checked the carb temp yet.. never thought of it.. but ill have to do that with the cowl on.. ive been tuneing it with the cowl off.

Where exactly would you cut the hole for carb cooling? Would this negate all of the reasons we should cowl the carb as far as stable air goes?

220 to 230 is on the hot side. Especially if you are hovering or flying where there is reduced air flow over the cylinders. JMHO but I think you may be overheating. The cylinder heads on my 3W 106 run between 180 and 190 with baffles. Also do you have the coated cylinder heads from AI.

yeah, tere coated..ill see what i an do to drop the temps down a bit..

the painted cylinders will run up to 40 degrees hotter than the non painted cylinders will because the pores have been sealed,but that's something they don't tell you when you get them painted like that,that's something they will only tell you if you ask!! another reason guys are having problems with the phenolic blocks !!!! it's alot easier to blame it on the manufacturer when actually a little info from the distributor would save a whole lot of stress for alot of guys who have the painted versions. proper cooling and lubrication is the whole key to longevity !!