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ZDZ 80 Hard to start

Old 10-07-2007, 06:22 PM
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gapple12
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Default ZDZ 80 Hard to start

Hello, I have an older ZDZ 80RV, copper head version, and lately I started running full synthetic Mobil 2T. The engine was easy to start before I started running this oil. Now the first initial start of the day takes a lot of flips. I first fill tank, then power on, not ignition. Choke full, flip prop about 5 times. Ignition on, flip till I hear a pop. Then choke off and flip till it stays running. This use to work good, but now I never hear the pop with the choke and I end up flooding the carb. So I have to let it sit and just flip and flip till it finally fires. Any ideas? Do I need to adjust the low speed? Maybe a different way to start these engines?
Old 10-07-2007, 06:27 PM
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gapple12
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Default RE: ZDZ 80 Hard to start

Oh, forgot to mention that I also just added a baffle to the cowl, not sure if that makes a difference. Also, the engine has been broke in to ZDZ instructions and had about three gallons of gas before full synthetic.
Old 10-07-2007, 06:33 PM
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ROGER RUSSELL
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Default RE: ZDZ 80 Hard to start

What did you change from and to?

What mix ratio?

Any needle changes?



I too am running that same oil in my OLDER (4 year old) ZDZ 80 at 32:1.

I have had success in starting it this way.

Ingnition on, choke on, couple clicks above idle, flip till pops, choke off and about 10-15 flips you can here it poping again, 5 or so flips after that and running.


You will get tons of ways to start an engine, this is what works for me.

I also have a ZDZ Blue Head and start it the same way, but it starts in about 5 flips after hearing it pop.

PS:

I have recently sold both planes that these where on.

Great engines.

Good luck and lets us know.
Old 10-07-2007, 07:11 PM
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bubbagates
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Default RE: ZDZ 80 Hard to start

Actually just about every ZDZ I have ever started for someone else (never owned one myself went like this and it seems to work everytime

it's the old 5-5-1 rule

Ignition off, full choke, full throttle 5 flips
Ignition off, full choke, no throttle 5 flips (gets the engine good and wet)
Ignition on, no choke, throttle to idle, one flip and she's running.

This all assumes you do not have the low needle too lean which is what it sounds like or even the choke is not closing completely
Old 10-07-2007, 07:46 PM
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gapple12
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Default RE: ZDZ 80 Hard to start

Yea, I thought about the choke not closing. I am going to tear it down tomorrow and look for the obvious. The ratio the engine was running was 32:1 on Penziol air cooled. I then switched at 40:1 with the synthetic Mobil 2T. Runs perfect, I still think its a little rich maybe on low end. But this problem just started. One other problem is it doesn't want to idle very low. I am going to try these other methods of starting it also. Thanks for the help.
Old 10-07-2007, 08:04 PM
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bubbagates
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Default RE: ZDZ 80 Hard to start

If it doesn't want to idle low check for an air leak while your at it or even the throttle plate inside the carb being a bit loose, mainly the screw that holds it on
Old 10-07-2007, 08:06 PM
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gapple12
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Default RE: ZDZ 80 Hard to start

Thanks, I will take a look....
Old 10-08-2007, 07:35 AM
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ROGER RUSSELL
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Default RE: ZDZ 80 Hard to start

I orederd three cases after reading this.

http://www.mobil1.com:80/USA-English...Racing_2T.aspx

Ordered from here.

http://store.avlube.com/mob1mx2cycmo1.html
Old 10-08-2007, 08:37 AM
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gapple12
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Default RE: ZDZ 80 Hard to start

Wow, I better get some more before there all out. They sale it at my local Auto Zone right down the street.
Old 10-15-2007, 12:39 PM
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ec121
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Default RE: ZDZ 80 Hard to start

I just got a plane with a ZDZ engine that I couldn't start Sunday afternoon. This was my first attempt at learning the recipe for starting. I flooded it because I wasn't familiar with the radio. The old owner had the choke on a slider and I got the open and closed backwards. Finally got it running but couldn't repeat it after I put the cowl back on. Will try again when I get a chance. What makes these things so hard to start? My 3W 85 twin starts right up with the usual choke and pop, then no choke and 4 flips. I saw the old owner start the ZDZ up with the 5/5/1 routine so I know it will run. Is there something about the way they are built that makes them prone to flood? I'm using the Mobil oil with 93 octane.
Old 10-15-2007, 01:18 PM
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Default RE: ZDZ 80 Hard to start

If it was still warm after you got the cowl installed you probably did not need to do the 5/5/1 thing. I'd also check your needles, you could be a little rich or lean on the low end, it's hard to say be the description after the cowl was put on.

I cannot say for certain why they start this way.
Old 10-16-2007, 09:00 AM
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Default RE: ZDZ 80 Hard to start

99.9% of the problems people have with starting ZDZ's is not getting fuel into them when cold. The choke must close completely or you're wasting your time and arm muscles...

That being said, if they're still hot they can be difficult to get going again. If it's still just a bit warm say after sitting for 20 to 30 minutes mine will usually start without choking on the first or second flip. Once it's been run that day and it's cold, like sitting for an hour or so, usually one flip choke on, choke off ignition on and they'll go the next flip.

They will start using what I call the "DA method" of flipping them choke on, ignition on until it pops then turning off the choke. That tells you there is fuel there, but they also wind up flooded when you do that so proceed accordingly if you do it that way and it will take more flipping.

But like I said, if it's still hot then it's strictly a guessing game and I've not found a perfect solution. Basically it's a lot of flipping but some guys will intentionally flood them so they've got a known situation, others just play with how far open the throttle is, some just let it cool off a bit. That's my preferred solution...
Old 10-16-2007, 09:42 AM
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Default RE: ZDZ 80 Hard to start

...some also change out the carbs to a walbro equivilent.

Chad
Old 10-22-2007, 10:15 AM
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ec121
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Default RE: ZDZ 80 Hard to start

Finally got mine(ZDZ80) going using the 5/5/1 method after I didn't flip it but 2 times the first start. First time it popped and died probably because I didn't get enough prime, then I played with the choke til it stated(just a few more flips really). 2nd flight I used 5 flips instead of the recommended two from the previous owner and it started as advertised. Engine is tuned right I just have to get the routine down. It ran well in the air with a 26x10. Not as powerful as the 3w85 but way more than adequate for the plane. I might be comparing apples and oranges too. The Super80 might be the equal of the 3W.
My 3W-85 can be finicky when it is warm. Sometimes one flip will restart it and other times it is better to wait a bit and let it cool off. The 5/5/1 is really only a few more flips than the usual "choke and pop" method. Even after the 3W pops it is still 4-5 flips with the choke off. Total time spent is about the same.
Old 10-22-2007, 10:29 AM
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Default RE: ZDZ 80 Hard to start

ec121-RCU, what do you have your 80rv installed on? What RPM do you get on the ground with the 26x10 and which prop is it? I have a blue head 80RV I'm about to start playing with, so I thought I would brush up on what you guys are seeing.

Chad
Old 10-24-2007, 03:06 PM
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ec121
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Default RE: ZDZ 80 Hard to start

I have the engine on a Wildhare Extra260 33%. No idea what it turns or what the plane weighs. I don't obsess about that kind of thing. Has plenty of power. It will launch the plane in about 30 feet if I hold a little up elevator and will pull good vertical for a long way. Loops as big as you want to make them. That is about all I need to know. I tried to hover it but I'm not that practiced and it kept climbing at half throttle or a little less. Should do OK if I try to 3D it. My CAP232 has a 27x10 3W85 on it and will climb forever. Still don't know what it turns either. I'm not trying to be smart about it. I'm just not concerned as long as it performs to my style of flying. As I am not racing, trying to get the last rpm out of a sport flyer is not real high on my "to do" list. Good luck with your engine.
Old 10-24-2007, 04:20 PM
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Default RE: ZDZ 80 Hard to start

ok...no problem, glad to hear you are enjoying your setup.
Old 11-11-2007, 01:04 AM
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Default RE: ZDZ 80 Hard to start

It's not always 5-5-1. The first number can be as much as 20 depending how cold it is, or how well the choke seats etc. Just as Wise Dick Hanson told me, keep flipping until you hear a squishy sound in the cylinder. That's when you know the prime is there. Then you can go on to the 5-1. So for me the other day it was 20-5-1. Listen for the squishy sound or you are wasting your arm/shoulder.

PS: I went to 2T also recently on my 50NG. It runs lean when switching from Pennsoil. You gotta richen the needles a bit, maybe an 1/8 or so. But if you were too rich with the Pennzoil it may be perfect with 2T. My guess is that your low end leaned out and it became harder to start.
Old 11-11-2007, 01:42 AM
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Default RE: ZDZ 80 Hard to start

On my ZDZ40, the sequence is 30-0-1. Usually there is no squishy sound as with DA50.

What is your mix ratio with 2T oil?
Old 11-11-2007, 11:43 AM
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Default RE: ZDZ 80 Hard to start

I usually run mine dry at the end of a flying day since they are stored inside the house, so it takes a bit more choking on the first flight.

Whether it makes a difference or not, it seems to me like they pull fuel better if the throttle is wide open and the choke on. So first flight I choke it with full throttle for 10 flips, then I close the throttle to just barely above closed as I can't hear what I call "the snotty nose" sound when the throttle is wide open. It's usually apparent within 5 flips of closing the throttle when I hear that sound. Choke off, ignition on and they go the next flip, on rare occasion two. This method works on both my 50 and 100.

While flying the 50 yesterday when it had sat long enough to cool off completely, 1 choke flip, choke off ignition on and 1 flip to start.

And yeah, when you change the oil brand/type (syn or dino) or mix ratio, you have to re-tune. I won't get into the brand/type debate as I've settled on a particular brand/type after trying number of them, but suffice to say it's a 40/1 mix....
Old 11-12-2007, 02:34 PM
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Default RE: ZDZ 80 Hard to start

ORIGINAL: nonstoprc

On my ZDZ40, the sequence is 30-0-1. Usually there is no squishy sound as with DA50.

What is your mix ratio with 2T oil?
32:1. I don't plan on ever going to 40:1. It's not messy at all at 32:1.

The squishy sound is subtle but I can hear it clear as day. If I don't hear it I keep flipping (calmly).

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