gobird

I recently purchased a slightly used ZDZ 80rv. I am not a newbie to gas, but not a old hat either. I have two G-62's with spring starters that start so easy as to make you spoiled. I also have a 3w 100b2 that starts just as easy. This brings me to my problem.

How do I reliably start the ZDZ every time? I have taken it to the field three times. The first time, it would not start, no way, no how. I was quite sure that I had gotten a bad deal. The second time, it started on the 2nd. flip and pulled strong. Great flying that day, always starting right up.

Today I had a chance to take it to the field, and once again, no starting at all. Wore out my arm, my patience, and probably the engine while trying, but not a single pop.

I have no idea what to try, or how to go about it. It seems like there are a lot of ZDZ users on the forum, and I am hoping you can coach me through making this engine start well.

Thanks

gobird

mrbigg

My Feedback: (21)

take a can of starting fluid with you. hehehe. seriously, my leafblower wouldn't start the other night after being in the heated garage (going out to blow some snow). i got tired of pulling so igave it a LITTLE SHOT in the air inlet and it lit up on 1 pull and stayed running. done it before on my snow blowere with no problems.

gobird

mrbigg,

Don't think that didn't cross my mind, what little there was left of it anyway! I had a sudden vision of blowing the head right off that 10:1 compression engine, and then I regain some control. By the time I was done today, I was ready to blow the head off however!

I should have included that I have both needles set at 1.5 turns open, and the engine is settup in an inverted position. That way, the starter fluid cannot blow the head off into another plane and make me pay for that too!

Diablo-RCU

My Feedback: (1)

Tell us your starting technique.

gobird

Diablo-RCU,

With the ignition cold and throttle full , I apply full choke, rock the prop forward into compression until I reach max compression, then rock it backward until I get out of compression, then repeat until I have done that about a dozen times. I read somewhere in the forum that this was the best method of prime for the ZDZ.

Once I have primed the engine with this method, I close the throttle to about 25%, shut off the choke, switch the ignition on, and flip, and flip, and flip, and fl ...... well, you get the picture. After about 20 flips, I get pissy, and repeat the process.

The one day that it ran, I used this process, and the engine ran great. This is what confuses me. Bad ignition would mean it should never run, dirty carburetor or bad gaskets should mean it never runs. All of this has occurred on freshly mixed gas, using Poulon oil at 40:1. I ran one G-62 and the 3w on this gas, and a friend ran his DA150 on the same gas. It is premium, following ZDZ's recommendation.

One last thought. I have read that the ZDZ's are prone to flooding, but I have no idea how to tell if it is flooded, other than strong raw gas smell from the exhaust, which by the way, I have never gotten. Both the Zenoah's and the 3w will drip from the carb, but how can you tell that method with a rear exhaust, inverted mount engine?

Gee, I really do sound like a newbie, I guess I must be!

gobird

TLH101

My Feedback: (90)

A friend has a ZDZ 80, and had the same problem untill he found the "technique". First, remember that is the ignition is let setting for a minute or so, it disables. a saftey feature.
Choke on, switch off, 1/2 throttle, 10 flips. Choke off, switch off, idle throttle, 10 flips. Switch on, idle throttle, 1,2, or maybe 3 flips, and it's purring. His ZDZ 160 is the same.

huey-pilot

My Feedback: (17)

I soldered the hole shut in the choke plate on my ZDZ 50 and then drilled a hole using a #60 drill bit in the solder, this moves the fuel much better when I choke the engine. To start I rock the engine back and forth between compression bumps with the throttle full on and choke on and ignition off and I watch for the fuel to move up the fuel line to the carb, when it is at the carb I give the engine 3 flips with the choke on throttle full on and ignition off, then I move the throttle to about 10%, choke off and ignition on, engine usually starts with 3 or less flips. In the past I used the factory method of flipping the prop with the throttle full on and choke on until it fired then choke off and engine to idle then flip it until it starts, I just about wore my arm out using this method so I tried various ways and found that the above is working very well for me. This engine is mounted inverted with a BCM muffler and has less than 3 gallons of fuel through it.

Diablo-RCU

My Feedback: (1)

Use a 3-line tank so the feed line to the carb always is full of gas. Throttle to idle, ignition off, choke on, 3-5 flips through compression. Turn choke off, throttle still at idle, turn ignition on and flip prop until it starts - usually within 3 flips.

Alternative method. Choke on, throttle at idle, ignition on, flip until it pops and runs for a burst. Engine is now very wet. Turn choke off, throttle at high idle, ignition on and flip until it runs - maybe 10 flips.

The 3-line tank is the key to a consistent start because the carb is always primed with gas and the line is full. With a 2-line tank and a fuel T, no telling how many flips it takes to get fuel up to the carb.

ROGER RUSSELL

My Feedback: (12)

I use your first method and works great for me, first start of the day may take a few more flips, but after that it starts pretty easy as described.

DMichael

My Feedback: (5)

My experience has been that, once you choke the ZDZ, you need to clear it out. I have had easy starts with multiple ZDZ's using a simple method:

IGNITION OFF
- choke on, throttle full open. Flip five times
- choke off, throttle full open. Flip five times

IGNITION ON
- choke off, throttle to idle. Flip once. Engine is almost always running on first flip.


If engine doesn't start, I cycle through the same process again. Make sure you have someone holding the plane securely even when flipping with the ignition off. Anytime you are flipping the prop with the throttle open you need to be very careful. In fact, next time out I'm going to start duing the same technique with partial throttle settings and see what happens.



Dave Michael

gobird

Wow!

Thanks guys for all the advice. I went out today and followed Diablo-RCU's 1st method and found that I had to modify it slightly for my engine.

Use Diablo's method, except for using full throttle instead of low throttle with choke on and ignition off. Bring throttle back to high idle, turn ignition on and leave choke on for 3 flips. Then turn off choke, flip twice and fly!

This seems completely repeatable, even after I let the engine cool back down to ambient temp and tried again.

I do have to admit that I was so discouraged yesterday that I was a little complacent today, not actually thinking it was going to start and tested the strength of the Biela prop with my right index finger, which is now about twice it's normal size -- ouch[:@] but it was a small price to pay for a technique that works.

I am just amazed at all the power from that ZDZ. It does not have that smooth, wonderful sound that the twin has, but amazing pull from a very light weight package. I have been lurking here on the forum for a long time reading about this engine from all its supporters and detractors, but nothing prepared me for the real thing.

Way to go ZDZ for building us such a great engine, and way to go to all of you who stopped by here to help me out. I am quite sure I was flooding my engine, based on reading your posts, and would not have figured it out without you guys.

Thanks again,

gobird