It turned out that all i needed was to take a blow torch to the plug, the zdz 40 apparently oils up after lots of gallons and needs a good heating to burn up. Engine is back to normal easy starting and a little powerhouse.


Thanks

Mark

Here is another runner...

os 1st 55cc gas engine

I have had my ZDZ50NG on the scale and here is the result.

-ZDZ50NG with sparkplug only 1306 grams
-With prop. bolts and washer 1359 grams
-Engine with bolts and washer,sparkplug,complete ignition and pitts-style silent muffler inc. bolts 1750 grams in total.

Does anyone have the numbers for DA 50?

And one question, the red bolts on DA50 is those aluminum??

Thanks

Christer

I had both..love them..DA was slightly easier to start, replacement ignition for ZDZ was more $$$, ZDZ used to need
higher octane gas. Both had great companies for service..
Today, I would pick me up a couple DL's for the price of one ZDZ or DA!

I've got the 50 NG and I think its the smoothest running gasser I've seen. Very little vibration compared to other engines. It turns a Menz 22-8 at 6800 rpm and I believe with some more run time it will get close to 7000rpm. It can be a real pain to start.......I'm talking 250-300 flips........UGLY.

Talked to Mike at Troy Built.......he said the low needle has to be out 2 turns to aid in better starting..........it worked. Flooding is more of a concern now......gotta watch that.

My other motors are Zenoah, Quadra, Brison and SPE. The ZDZ is my favorite for flying but, not for starting. You can't adjust the Walbro carb like you would on the other engines if you want it to start.

200-300 flips means you need to use the choke to get that fuel up there. try 10-10-1 and if it doesn't start repeat with 5-5-1.

No bother to start, nothing like a DA you need to use either the 5 choke on full throttle then 5 full throttle then ign on throttle to idle and one flip it will go, then mine start after 1 flip every time once first run.

Or if not starting full throttle and choke till it fires then the 5-5-1 works

Ive had 13 gallons of fuel through mine and it pulls like a trooper throttle response is superb. Just running my super 80 in also.

Mark

I guess I should have detailed my ZDZ experience.........I know about the 5-5-1 procedure and I've tried every variation you can think of.........what ususally happens is it won't start so, I figure it doesn't have fuel to the carb yet and I use the choke for a couple more flips....then it's flooded.

The ignition works fine........ new plug..........new gas........cleaned the carb..........I can watch the fuel line and tell when fuel gets to the carb........Right now the H needle is open 1 1/4 turns, the L needle is open 2 turns. The engine runs great if you can get it started. A hot restart is not a given either. I have to open the throttle and flip 5 times to prep for a hot start.

I've been fighting with this engine for almost 2 years.......it probably has 4 gallons of fuel through it. If I didn't love the way it runs, I would have quit on it long ago. It has to be something to do with the Rotary Valve induction. No one seems to be able to explain to me how that differs from a Reed Valve and why it makes these things such a bear to start. Another issue is the spark plug seal.........you have this cup the plug fits in before its screwed into the cylinder. The cup must seal to the cylinder and the plug must seal to the cup. Mine doesn't seal perfectly and I can accumulate an oily residue in my plug cap. I hesitate to tighten the plug "white nuckle" tight to try and force a seal. Any thoughts on that?

I'm still trying to find the correct combination of throttle and choke to get this thing started in a reasonable number of flips.........The L needle open 2 turns has helped.
Currently, I will start with the 5-5-1 drill.......if that doesn't work, I close the choke and flip till it pops, then kill the ignition and open the throttle and flip 5 times, then go live and flip till it starts with the throttle a few clicks above idle. My goal is to get a start with less than 50 flips.

As I said, a hot start is not a one flip deal........you gotta kill the ignition, open the throttle and flip 5 times......then go live and it usually starts.

Anyone that is interested in purchasing a ZDZ 50 and does some web research will soon run the other way. When I have mine at the flying field, I usually have a crowd assemble and give me absolutely unusable advice until I get it running.......it's become a tradition. Think any of those fellas are in the market for a ZDZ? Wonder how many times they've retold watching this guy they know try to start his ZDZ for an hour. Not the kind of "word of mouth" advertisement most companys want. I am amazed this engine is still for sale and I'm amazed ZDZ hasn't gone away from the Rotary Valve induction.

Something is definitely wrong with engine, carb or ignition, im in the uk and a whole load of us fly zdz engines they are flawless, show pilots and all. I would be sending the motor in for a check myself as this is definitely not the norm.

Im no way connected with zdz but it is my engine of choice, runs so well. Shame youre flying buddies are seeing a bad example of this engine as this is definitely not the norm, i run a DA50 also and just like them both but for me the zdz has the edge.

Mark

I have a ZDZ 50NG and its an AMAZING engine, very smooth, good power, amazing transition, very reliable in fact in hundreds and hundreds of flights i have never had a single deadstick with it, and its very easy to start, i just start it like any other gas engine, ignition on, choke on, flip the prop till it pops, after that take off the choke, starts on the first 3 flips no problem. There was a batch of them that had a defective carburator, and that caused the hard to start problems, so check that! Anyway mine is like +6 years old its one of the first 50NG and it still runs like a champ!!

Daniel

Here is a video of it (ZDZ 50NG) on a PA Edge 540, its from 3 years ago.

PA Edge 540T 3D (3 min 8 sec)

Daniel

Awesome vid Dan. I bet PA sold a pile of these things after people saw this video.

Originally Posted by JoeAirPort

Awesome vid Dan. I bet PA sold a pile of these things after people saw this video.

lol thanks Joe, although that video is really old, over 3 years old!, i think flying has changed a bit now As a funny fact, i just took out my ZDZ 50ng and installed a brand new prototype engine in the Edge for testing! we will see i will be posting video soon!

Daniel

Originally Posted by Roknhs

Another issue is the spark plug seal.........you have this cup the plug fits in before its screwed into the cylinder. The cup must seal to the cylinder and the plug must seal to the cup. Mine doesn't seal perfectly and I can accumulate an oily residue in my plug cap. I hesitate to tighten the plug "white nuckle" tight to try and force a seal. Any thoughts on that?

I had this problem on my ZDZ40. I emailed Mike at TBM and he told me what to do. Thoroughly clean up your head and threads as best you can. Then put Permatex ultra copper RTV around the retainer ring where it contacts the head. Do not get permatex on the plug threads! I torqued mine to 15 ft lbs. Let the permatex dry overnight. Problem solved.