ZDZ Fans and those who aren't - I need yourhelp!

Last June I purchased a ZDZ 40 RV and at first everything seemed normal. After fuzzing around for the summer (ZDZ has a whole procedure ...) I still experienced some reliability problems and almost ruined some planes due to dead stik! A friend of mine told me that I should send it back and get it fixed. I did and they send me a new engine because they did not have the time to do the fix! Well, the bad part: Once again breaking in the engine and the carb was offset differently and I had to change the engine mount on my planes - ggrrrhhh. Now I experienced a new problem: the new ZDZ40 RV is a pain ... to start. I heard from another friend that I had to start it at at least half throttle and ... that's scary - but it somewhat works!
For break in purposes I run the engine on a big trainer (Triple fun). The new engine idles a lot beeter than the old one and puts out a lot more power but - it just quits out of the blue!!! I fly full throttle and suddenly the engine stops. I checked the fuel lines, gas, high end ,,,,,,,,,,, I am just getting sick and tired to have dead sticks for I don't know what reason and I definitly don't want to dead stick my Giles / Extra!!!!

Can anybody help me? If ZDZ can't get it done - what would be an alternative - and NOT a challenge???

Thanks for help
Rainer

I felt the 40-1 oilo mixture for beakin was fouling plug on mine. Seemed to run better when I went to Honda Synthetic. Also, the low speed mixture setting is critcal and had to be readjusted a couple times on mine... Also seems to run better on 6 volts on the ignition.

I put a 2200 mah li ion battery on both ignition and radio/servos. This is taboo but works fine for me. I use a 6 v regulator.

There were times when the motor wouldn't even fire for me at about 5.3 v or less on the ignition.\\

Just some of my experiences, for what it's worth.

Fox35

[link]http://www.rcuniverse.com/forum/fb.asp?m=1353135&key=first%2Cstart%2Cflip[/link]\

See if anything here can help you.

Gunny

Gunny!
Thanks for this hint. An excellent write up, covering most of the problems I experienced with this motor - except one: why does it quit during full throttle (no stutter which would hint air in the fuel line - nothing). Runs great and than - quit?!?!? Als, what about running 5 cells for ignition rather than 4 - would that help for starting? I really would just love to fly and not fuzz around all day.
Thanks
Rainer

Usually an engine that just "shuts off" at WOT is running into one of two things. . The ignition is overheating and just shutting down, and will restart normally once cooled off (land and it flips and fires fine. . very frustrating) OR that the carburetor is not able to draw gas for some reason and basically puts a vacuum on the fuel line, inducing vapor lock and shut down. The fuel delivery problem will show signs of hard starting, necessitating choke and numerous flips to restart, and then will run fine until enough heat builds up at full throttle to again vapor-lock the gas in the line.

I'd chase the fuel delivery problem first, if I was you, checking all the lines, and for debris in the tank. I'd also shorten the line as much as possible, zip-tie the ends to the nipple on the carburetor and tank, AND route it as far from heat (even wrap it with insulating foam if necessary) to prevent this phenomenon.

The ignition problem, if it is occuring, CAN be caused by a questionable switch contact going intermittent from heat as the ignition demands more current at high power settings, the same for a bad connector anywhere in the circuit, a weak cell in the ignition battery pack which will have the same current-limiting effect under higher amperage loads. I'd advise checking every connector and the switch, do a 3-4 amp load test on the wiring to check for a voltage/current drop among the the components, and advise going to a 5-cell pack with a 6 volt regulator.

There's no reason TWO engines should experience the same exact problems under heavy loads, and the issues above are the most likely to have occured.

Best of luck with the little beastie.

RMM, I had the same problem your having with the engine quiting at wide open throttle. Went through everything, new gas tank, new gas lines, new plugs, new ignition module, turned out to be the switch. Yes it was a brand new switch, but somehow the harmonics of the engine and airframe vibration, made the contacts open at WOT. Went to a HD switch and it has not even sputtered since.

Well said guys, Thanks for helping out rmm

Gunny

No disrespect meant, but I (and many many like me) have not had any issues with the DA~50....just a thought if you get tired of playing with the ZDZ.

Guys,

Thanks a lot for your moral support and the very good hints. Yes I am using an electronic switch (security measure to shut off the engine) which I will eliminate - who knows? Second I will take apart the carb to see if there is any debris - does anybody know where I can get replacement parts for walbro. Then I will go through the procedure that Gunny wrote up - and if this all doesn't help I will send it back to ZDZ. The engine is less than a few months old!!!!!

Thanks again!
Rainer

Go ahead and drop the money on a DA-50 it will be trouble and temperment free from the factory... just my experience[8D]

You can get parts for the Wabro at most places that repair lawn equipment, take the carb with you because they will need the numbers on the carb. The rebuild kits that I have purchased cost between $7 and $11

ZDZ - the never ending story ...
Okay, this weekend I gave it another try with the zdz.
Here is a short summary:
- I took the motor off the plane and mounted it on a board, no extras, security switch what so ever - plain vanilla setup
- I printed out Gunny11 instructions and went to the field
- After mounting it .... I right away used the setup suggested by Gunny11 - H 1 and 3/8 L 1 and 3/4 settings
- I primed the engine (full throttle, choke on, iginition off) roughly 6 times/flips
- Choke on, throttle idle, ignition on - the beast fired on the first flip
- Choke off, throttle idle (a tick more), ignition on - 2 flips and the beast was running

hmm - and now????
I was ready to throw it away and it performed llike a charme! I still need about 15 flips or so once the engine was hot, however, according to Gunny11's instructions, I probably will be able to get that fixed as well.

The idle was ok for a motor with only 20 os of gas through it - I had it stable at around 2000 rpm with a 18x10 Bambula. Full was okay too - 7650 rpm.

Gunny11 I need one more hint from you: If the engine is running WOT it has a nice solid sound - very clean, however, once in a while a little this sound is interrupted by the sound the engines do if they run a bit below the full throttle (don't know how to describe) and then it goes back to the nice sound. What can that be? Not enough fuel? Large tubing???

Summary:
First of all I am quiet p.o. that nobody else was on the field. They probably won't believe it (if I have trouble the next time?!?!).
Second: I don't care as long as the ZDZ runs and does what it should do - take my nice Giles and Katana up there ...
I guess I will have to find out what I have to eliminate from my setup to find the failing part.
I am still somewhat reluctant but the zdz performed 1A today - really!

Regards
Rainer

No gasser NEEDS large tubing....

sorry I mis read and gave wrong answer.

Hi, so what do you think could that be? Any idea if it's not the tubing?
Rainer

I had the same problem on a G23 once. It was vibration, just at certain speeds, foaming the gas up and then sucking air into the carb. I foam mounted the tank and got rid of the problem. Another thing I do with all my gassers now is to use the common chainsaw type clunk in the tank. It helps prevent sucking air into the pickup line.

If the engine is running WOT it has a nice solid sound - very clean, however, once in a while a little this sound is interrupted by the sound the engines do if they run a bit below the full throttle (don't know how to describe) and then it goes back to the nice sound. What can that be? Not enough fuel? Large tubing???

Hmmm. Maybee it's surging for fuel? But if I recall correctly on mine, I think it did it also. So I did do a few things but I dont know witch solved the problem. Larger fuel tubing, no filter on the main line, Larger brass tubing for the pick up. You may want to try to open or close your high needle a hair. But Are you still on your first gallon of fuel. Is your carb. getting enough air?

By the way I went flying a couple of weekends ago and Guess What, It started on the first flip after 3 months hybernating in the hanger for the winter. I'm gladd it's getting better but be patient. As far as the warm / hot start, try to keep the throt. idle on the normal or low side. I noticed if my idle is too high, I'ts harder to start.


Keep up the good work and patience.

Let me know how it goes.

Glad to help

Gunny

rmm will you be trying to run the engine again this weekend?

Gunny

Gunny

I ordered the airfilter. If it shows up before the weekend, I will run it again and do some adjustment so the will run fine with the filter. I also will have to test again my kill switch. I use the RC100 from RCATSYSTEMS (http://rcatsystems.com/electronics.php) and I don't know if the vibration could have caused the problems. Once I confirmed that the setup will work I will put the motor back into the Giles and ---- hope I don't have a dead stick / need 200+ flips to start the engine. I will let you know. Question: Do you have any experience with the RC100?

Regards
Rainer

Negative on that.

Gunny