jmiracle

My Feedback: (9)

Can anyone tell me what might be some symptoms that the timing is too far advanced on an engine like the ZDZ 50?
I have a brand new 50, and it's been a pain to start since day one. It pops and sputters like it wants to go....and frequently shoots flames out the exhaust. I've had it running a few times....when it does run, it runs very nice.
Finally, after a bit of searching on RCU, I decided to verify the location of the ignition sensor. Mine was about 13-14mm past the sensor at TDC when the manufacturer says it should be 6mm.
I set it back to 6mm, but it's now too dark to go try to start it again.
I feel pretty confident that this has been my problem....but just out of curiousity I want to know if what I have been experiencing is consistent with the timing being advanced that much.

Thanks,

jmiracle

My Feedback: (9)

You're probably right about it being retarded....the engine is inverted, so it's likely I got my self confused as to where the piston is when ignition takes place.

I've also read 7mm for the 50, however the manual that came with the falkon ignition doesn't specify clearly. It says 7mm for the 40 and 6mm for the 60. The 50 isn't even listed.

But regardless of whether its 6 or 7, I should still see a very noticable difference the next time I try to start it, correct?

I'm thinking I'll have to go in to work late tomorrow so I can try to start this thing one more time....I'm dieing to know whether this fixed my problems or not.

samsrc

My Feedback: (4)

That's funny you mention that, because I fired mine up last night in the garage, and I had the same results. Flames shooting out of the exhaust, tough to start, etc. I installed it the way I got it in the box, with no measuring or adjusting, figuring that it was set like this from the factory. I think that it is too far retarded as well. I set it closer to the magnet, but then it got late, and I didn't have a chance to try it again.
Hopefully tonight.

We will see

jmiracle

My Feedback: (9)

well I'm afraid I have bad news....
This wasn't the magic setting that solved all my problems....though I do feel things have improved some.
It doesn't shoot flames out the exhaust anymore, and in fact, I did succeed in starting it...twice!.
But after that, it would only start for a couple of seconds then die before I could get my hands on the transmitter to feather the throttle.

Samsrc, please let me know how things go for you...keep sharing what you learn! I'm in the same boat as you, and figure two heads on the same problem has got to be better than one!

samsrc

My Feedback: (4)

Which way did you go with the sensor???

Did you go closer to the magnet?? (closing the gap)

Or further away from the magnet?? (opening the distance)

jmiracle

My Feedback: (9)

i moved it closer to the magnet....so that it almost exactly matches the picture included in ignition manual.

samsrc

My Feedback: (4)

Hmmm...well that sounds like the right thing to do, but I would recheck the distance, and if it's right, I would then check your actually needle valve settings. It sound like you might be a little lean on the low end. Try riching it a bit, and see what happens.
I will play with mine once I get home tonight, and let you know how I make out with it

jmiracle

My Feedback: (9)

I think I will double-check the distance. I set it to 6mm, but I've read numerous posts on here that it should be 7mm.
I'll give that a try and see what happens.
A lean low-end also crossed my mind. I started with the low and high 1.5 turns open as suggested in the manual.
If I remember right, these were the settings it was at when it did start.
When it started, I got the rpms up and it seemed just fine, but with a rather high idle....so I backed the throttle trim down. This got it idling nicely, so I advanced the throttle....running good on the high-end.....but when i backed off the throttle....right when I got to idle, it sputtered and died.
I made several more attempts to start it.....and this is when it would start for a couple seconds, then die. So I richened the low end in 1/4 turn increments until I was 2.5 turns open. There was almost no difference. It would start, then almost immediately die....some times it would run for several seconds, other times, just a couple.

samsrc

My Feedback: (4)

hmmm....it sounds like it might be a little flooded. My suggestion is to shut it down, reset everything according to the manual, and try again. I'm sure you will get it.

jmiracle

My Feedback: (9)

Yup.....eventually....just gotta keep at it I guess. This is my first gasser, so I'm learning as I go here.
When I get home tonight, I'll reset everything and see what happens.
Thanks for the tips....and let me know if your's works out.

Flypaper 2

Sound like it may be loading up and dying. Try 1 turn on the low speed mix. Takes a bit to get it dialed in. Initial setting are just a place to start as no two engines end up exactly the same.

Maudib

My Feedback: (51)

Jere's the link to the settings... it IS 7mm

RC Showcase sensor setup


On the same page is carb setup... good info...

jmiracle

My Feedback: (9)

OK, here's the latest...
I haven't yet reset the timing to 7mm. I will do this later tonight.
I set both needles to one turn out....this seemed to help.
I can now get consistent starts, HOWEVER....
It only runs at idle....it sputters and quits with even a few clicks of throttle. If I don't touch the throttle, it will just sit there and run.
I thought this seemed like it might be lean on the low end, so I gradually richened things up to 2 turns. It only seemed to make it worse.
I was going to back it off to .75 turns, but then it started acting like it was flooded, so I've quit for now. Probably won't be able to get to it again until tomorrow.
Any thoughts?

lewdfinger

Had the same problem with my ZDZ 40 after I got it back from warranty repair. Would pop after two flips with the choke closed and then would start with a roar and then quit, like it was starving. I had the exact problem as you, because in frustration I would choke the hell out of it until it flooded, and then it would backfire as it cleared out with more flipping. I forgot that on the 40 the rotation of the throttle butterfly is backwards to what I'm used to (Bing carb). That is, when the throttle pushrod is all the way forward, the throttle is closed! I had my throttle almost wide open when I thought is was only open a crack . I simply reversed my throttle servo and open it two clicks - now starts with two choke flips and two or three more with the choke off. Don't know if this applies to your situation or not.

There are other threads about starting ZDZ's. Older carbs had a hole in the choke butterfly that was too large so the carb wouldn't draw - the 50 undoubtedly has a new Walbro.

Could your engine be sucking air? Check carefully around the carb spacer for warpage or cracks, and for cracks in the crankcase. When I first got my 40 it started OK but ran really crappy until I figured out that it came to me with the carb spacer installed upside down and was sucking major air - I posted pics in a different thread http://rcuniverse.com/showthread.php...330&forumid=37

Good luck

KD

Maudib

My Feedback: (51)

See here:

Falkon Website:

It has a nice flash anim (but poor english)

It does sound like the low end and high end may be too rich...

Also when you get CLOSE.... move the needles just a couple hairs...

Maudib

My Feedback: (51)

On the ZDZ 50:

From the front of the engine, when inverted, the sensor bracket should be up against(to the right) against the screw as far as it will go. This is approx 7mm(not 6mm), which is the same for the 40.

jmiracle

My Feedback: (9)

OK, so I set the timing to exactly 7mm. Starting got easier, but it still doesn't run for very long.
This time though, I left the cowl off...and one time I got lucky enough to get to the carb with a screwdriver before it quit. With the carb at 1 turn out initially, I had to richen it over 1 full turn before I got a nice steady idle. I could throttle up till just when the high needle would kick in, then it would die off, so i assumed the high was too lean as well...I got a couple adjustments in before it died.
So I try to start it again....but now with the low end so rich, it's backfiring out the exhaust again! Leaning out the low end solves the backfiring, but it won't run very long.
So I guess now I'm starting to suspect an airleak someplace. Hopefully it's just a simple thing as was mentioned earlier and the gasket is flipped around.

Maudib

My Feedback: (51)

FIRST: The High End DOES effect the low end... so as you richen the high end you may need to lean the low end...

If that doesn't help:

Check for fuel tubing kinks that would cause intermittant or constant leaning.

As you said, check for leaks in the tubing or around where it plugs onto the nipples. Use clamps or zipties to seal well.

Check the tank too and whatever lines you might have... (make sure vent is clear an unconstricted, if you have a fuel filler (not a fuel dot) bypass it temporarily.. they can leak air...

Also make sure your ignition battery is of good quality and fully charged.

Inspect the inside of the carb for debris that might have been sucked in...

Just the usual things to watch for...

iwannafly

My Feedback: (1)

Fighting my zdz 40 trying to get it right. When I move the sensor to the right against the screw is that looking at the inverted engine from the front or rear?

jmiracle

My Feedback: (9)

But if I leaned the low end, the engine would quit...

So....checked fuel lines, no kinks whatsoever...smooth bends, and short run from take to engine.
Tank is 3-line setup...one to carb, one to vent, one fuel-dot style filler. I double-checked my hookups, those are correct.
Fuel lines have been zipped tied to nipples...this was done a couple nights ago.
I have also tried two different ignition batteries....no difference in the way the engine runs.

So that leaves me with the carb. One thing to note here that I haven't mentioned before. I did rotate the carb 180degrees on the back of the engine to make it easier to hook up throttle and choke linkage. Though i don't see how this could cause problems...thought I'd mention it.

I also checked the gasket...theres only one way it can go on, and it was on the correct way.

I inspected the inside of the carb as much as I felt comfortable doing. This included popping both sides off and checking for debris.
On the side closest to the fuel-line nipple, there is a small mesh screen under a gasket. I saw some gunk on that screen....not much, but noticable. I cleaned it out until I could not see any more particles on the screen.

If this thing doesn't want to run right after this....I don't know what else to do....

GMM

J.

I had the exact same symptoms as you. Mine would run however, not consistently between runs. It was hard to start, and would backfire just like yours. Here is what I did.

1. Check the fuel tank. Make sure your fuel tubing inside the fuel tank is secured, and will not leak air when the fuel level drops below the stopper. Check the rest of the fuel system to make sure it is tight. I did this

2. Low end should be at least 1.5 - 2 turns out. If it is too lean, it will quit when you throttle up. Try to advance the throttle quickly to about 1/3. It should spool the engine up without hesitation. If it quits it is too lean. The high needle should be about 1.25 to 1.5 turns out. If you advance the throttle and it quits when you reach 1/2 throttle or more the high end is too lean. I did this.

3. Take the carb off and check the little hole in gasket, and make sure that it is not clogged with sealer, and it is lined up with the hole in the carb. This makes the fuel pump work. I did this.

At this point my engine would run fine one minute, and would not run the next. Just like it had done in the beginning. Finally I ended up calling Mike at RC showcase, and he sent me a new carburetor, and it runs perfectly now low needle is about 2 turns out, and high is about 1.25 turns out. It idles extremely low, and tranistions from idle to full throttle immediately regardless how long it idled. My timing is at 7mm. Apperantly something was wrong with the carb that was originally on my engine. I wasted alot of time trying to get mine to work until I put the new carb on. Night and day difference. Do yourself a favor and call Mike, he will get you fixed up. Please let us know how it works out.

Greg

GMM

J.

Just read your last thread. Put your carb back the way it was. There is a hole in the spacer that must line up with the hole in the carb to make the fuel pump work. If the hole does not line up the engine will not get fuel after the initial choke. It is way too lean. Hope this helps.

Greg

Flypaper 2

J Miracle;
Sounds like you've got the low speed in the ballpark so leave it at one turn for now. Now start with 1 1/4 turns on the high speed and open it in 1/4 increments until it picks up when you open the throttle without quiting. if that doesnt work your problems are elsewhere.

jmiracle

My Feedback: (9)

OK...I just popped the carb off to check what you're talking about.

Now the gasket can only go on one way...which puts the hole in the gasket on the opposite side of where the small hole on the back of the engine is located.
On my engine there is a groove machined all away around the intake hole on the back of the engine.
So in other words, fuel can enter the hole in the gasket, flow into this grooved ring, and into the hole on the opposite side of the intake.
When the gasket is installed in this way, there is a small hole on the back of the carb that does line up with the hole in the gasket.
So I'm pretty sure things are lined up as they should be.

Flypaper 2

J Miracle:
Just read your post about inverting the carb. Greg is correct. Pulse hole has to line up to operate the fuel pump.