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Please Help. ZDZ Super 80 RV J won't start.

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Old 06-15-2008, 06:59 PM
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Chas_97
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Default Please Help. ZDZ Super 80 RV J won't start.

Bought the engine brand new from Chief Aircraft. It came with a Tillosten carb. Ran it for about 20mins. Ran very rough until my prop bolts got sheared off b/c I did not seat my prop bolts.

Sent the engine to RC Showcase so I could get a new prop washer. Just got the engine back from RC Showcase. Mike was nice enough to put a Walbro carb on it for free. But now I can't get anything more than a "pop". It won't start. Tried all low needle settings possible.

Should I go back to the Tillosten carb?

Can anyone help me on this problem? I'm ready to fly.

Thanks,
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Old 06-15-2008, 09:20 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Finally, after adjusting timing (by way of moving the ingnition sensor closer to top dead center). It should be noted that top dead center is EXACTLY where the ZDZ instructions say it should be. It's just that maybe the ignition sensor needed to be just a hare towards top dead center. The magnet falls DIRECTLY on the web of the crankcase at top dead center.

The engine actually runs great now, and still may need to be fine tuned.

I must also confess that I changed the spark plug out at the same time I moved the ignition sensor by about 1.25mm. he he

One thing learned here is that ignition sensor location doesn't always go on the line. Sometimes maybe a mm or so may be needed to help starting.
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Old 06-15-2008, 09:37 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Does anyone know how far the center of the ignition sensor should be from true top dead center?
thanks,
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Old 06-16-2008, 10:06 AM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

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Old 06-19-2008, 01:35 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Well got the ignition sensor set 6mm from magnet at top dead center. The engine is a little easier to start, but still not really what I would call "easy" to start. My dad suggested 1/2 choke instead of full choke on the butterfly valve so I'm going to try that. We suspect it may getting too much fuel with full choke. We are seeing quite a bit fuel dump back out of the carb when we go from full choke to zero choke with the butterfly valve.
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Old 06-19-2008, 01:43 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

...if your low needle adjustment is too far lean, or rich, it can be more difficult to start. Also make sure you are running a fully charged ignition pack. I know many ZDZ users have good luck with the 5:5:1 starting method for a cold engine.

ignition off, choke on, 5 flips
ignition off, choke off, 5 flips
ignition on, choke off, 1 flip

I would rather guess that fine tuning the needles might help you with starting ease...
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Old 06-19-2008, 02:37 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Every one of us that own and love our ZDZ's will tell you that if you have the low speed needle set perfectly, it will be a little pain to start. The trick is just a click or two more of throttle trim.
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Old 06-19-2008, 03:27 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

correct, make sure the choke butterfly is closing as tight as possible
I tuned my ZDZ80 to run with nice transition and little midrange burble
but it is a ***** to start
it used to be 5-5-1, now it is like 15-5-1

you should as an experiment, do some choke flips without ignition on and then take off the plug to see if it wet at all to get an idea of what is going one
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Old 06-19-2008, 10:52 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

If you get enough of a prime it should start fine. If the fuel hasn't arrived yet those first 5 flips may not cut it....hence the extra 10 to equal the 15-5-1. You should hear a squishy sound if fuel is in the cylinder. Mine takes a lot of choking and priming. The leaner the low needle the more priming it needs. That's how miine are tuned and they run great.
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Old 06-20-2008, 07:26 AM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Rocking the prop back and forth with choke fully closed is another way to prime the engine quickly. You can watch the fuel gets sucked to the carb through the tubng so fast. On my ZDZ40, I only need to do it 5-7 times to get the fuel in.
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Old 08-29-2008, 03:01 PM
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Default RE: Please Help. ZDZ Super 80 RV J won't start.

Well my super 80 is starting to break in and is starting easier, but still takes about 15 flips with ignition off and choke on. Seems like going straight to ignition on with three clicks on the throttle starts best. Eliminating the second step in the 15, 5, 1 sequence seems to work better for me. The engine is really a great performer, but is a pain to start much of the time.
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