pfact

My Feedback: (92)

Hi engine gurus, I need some help with a new ZDZ 210

The engine was bought last fall for a 3.3M C-ARF Yak. I got it from RC Showcase with a set of JMB headers and canister mufflers. The plane is ready to go except for the engine. I was able to get it to run a single time in January but not since. I returned it to RC Showcase last week and they say it started easily. The ignition was damaged in transit to them so they replaced it for me (I'm not sure if they ran it with the new ignition).

I sent the engine to RC Showcase in November to have the carb inverted. They drilled a new pulse transfer hole in the phenolic plate under the carb. The one time it did start was after the carb was inverted. The carb draws fuel well to the engine - repeated flips of the prop produces a pool of gas in the carb around the choke plate and the crank case is wet with gas. I inspected the carb after trying to start it - it was filled with fuel but otherwise perfectly clean, all the valves and gaskets seemed fine. The needles are at the factory settings and I have been using the starting method advocated by RC Showcase. I empirically replaced the clunk with an unfiltered one and made sure the tank vent is patent. The tank sits slightly above the carb and I have used new fuel (with 1:32 Penzoil Outdoor Oil for air cooled engines).

The ignition produces a bright spark from both plugs. I have checked the voltage going to the ignition (5.5v) and even bypassed the on board battery and ignition cutoff. I don't have another ZDZ ignition to try and wonder if it's worthwhile to try one from a DA150.

Fellow club members who are better with gassers than I have looked at it and are similarly puzzled. The only thing I have noted is that there is almost no detectable gas in the cylinders, even after many flips of the prop, which makes me wonder if the transfer ports are plugged up. Notably, I had difficulty with a ZDZ 40 F3a last year - it took 3 trips back to RC Showcase to correct a bad ignition and some spark plug confusion. Eventually Mike Dooley sent me a new engine which ran beautifully right out of the box (they provided excellent service although making contact with them required a lot of patience).

I have tried everything I know, I can't even get the thing to make a "pop".

Phil

rmh

IF the carb is wet and the throttle plate goes in the correct direction and servo throws the throttle plate the correct direction-- the next point of interruption is th rotary valve in the rear housing
Unless this was somehow inadvertantly mis timed , the engine should - (will) run - I have used these and they are one flippers if all is correct .
The DA ignition will not fit the spark plugs -
You can not plug the transfer ports - impossible.
somewhere along the line here -we are mis communicating as spark and fuel always create a bump when pulling the prop thru on a cool engine.
To repeat basic
carb throttle plate MUST be travelling correct direction
then - a cold engine with choke closed and throttle plate slightly open - should pull fuel up th line each time th prop is flipped =not hard -just flipped.
If fuel doesNOT flow up the line to the carb STOP = the choke is not fully closed -try a thub over th e bypas hole in th choke - then flip (IGNITION OFF!!)
Once this is correctly established - the engine should pop -perhaps not run -but pop
The mod to the phenolic ONLY affects running condition as it pulses the demand regulator in the carb.
I can't help furthe as you say there is spark - I am assuming 35-1 oil reg gas mix.
plugs at aprox 20-25 thou gap.
No plugged exhaust (stoppers left in exhaust I have seen this!!)

pfact

My Feedback: (92)

Thanks for the helpful thoughts Dick,

The fuel travels nicely from the tank to the carb, the carb chambers are filled with fuel, and fuel drips from the choke plate if left closed - all seems fine in this regard. I am absolutely certain the throttle plate is moving in the correct direction - the throttle servo is pulling against the spring and away from the idle screw and when the choke plate is open I can the throttle opening the butterfly valve. I have even tried starting it with the throttle one-quarter to half open. The plug gap is 0.23".

How do I know if the timing of the rotary valve or even the timing in general is OK?

Shouldn't repeated flipping with a closed choke flood the cylinders? After hundreds of flips I have yet to see a drop of fuel in the cylinder and I certainly haven't seen a pop.

Phil

rc bugman

My Feedback: (30)

Pull the plugs and inject a little fuel into the cylinders. Replace the plugs and flip. If there is spark, you should get a pop and short run. Then you will know that it is between the carb and the cylinder.

Elson

pfact

My Feedback: (92)

Elson,

How much fuel would you put in?

rc bugman

My Feedback: (30)

A little squirt in each cylinder. Too much and you flood. A little and you will get a pop if the ignition is good.

Elson

rmh

Throttle start position only slightly open never more than that -EVER
Hundreds of flips - stop -something is wrong .
The position of the rotary valve is difficult to describe -and must be looked at with carb removed
basically it opens just as pistons start outbound BUT this is easy to get wrong so do not mess with it ask Dooley somewhere we ar missing a basic
are you certain the exhaust ports are NOT plugged up?

pfact

My Feedback: (92)

Libby,

Exhaust ports are definitely open.

I put a few cc's of gas in each cylinder head, reinserted the plugs and flipped the prop --> nothing. But, then I figured I'd try the usual starting procedure and a got a single pop (first one I have heard since getting the engine back). I tried it a second time and got the prop to spin once (probably because both cylinders fired). This seems to reinforce my hypothesis that no fuel is getting to the cylinders.

Any more thoughts?

Phil

soarrich

My Feedback: (98)

I hope this isn't insulting, but do you know the carb is on the right way? The L needle should always be the closest to the engine.

pfact

My Feedback: (92)

It never hurts to ask. To keep me straight - the choke and throttle arms won't fit if it's on backward. Besides, it is oriented the way RC Showcase had it when they got it to run.

soarrich

My Feedback: (98)

pfact

That didn't really answer the question. RCS said they ran it that way, OK if it's a Walbro carb the L needle is the closest to the engine, did you check that? Ronnie said "Trust, but verify."

Hawk-i

Pfact, based on my ZDZ 80 having similar starting symptoms, and 100's of flips, and trying everything you mentioned ... my eventual fix was a new Walbro.... I even tried a rebuild kit but that only helped it start up and then after leaning the carb so it would transition well enough to fly I could never get it to restart without richening the carb again. Before a new carb, I suggest you try openng up the needles to see if you can get it to start-even if it is sloppy rich.

soarrich

My Feedback: (98)

Any news on this engine problem?

dirtybird

My Feedback: (5)

A gas engine needs three things to run:
1. Fuel
2. Ignition
3. compression
If you put fuel in the cylinder and it don't run for a short time, then you don't have ignition or compression.
Remove the plugs. and hold them against the cylinder and turn the motor with a starter. Any small starter will do with the plugs out.
You should see sparks in the spark plugs if the ignition has the proper power to it. If you don't, get a new ignition.
If you do, you have low compression. It probably will improve when broken in. Find a starter that can turn it over at a good clip.
If you have fuel and a spark you will probably be able to get it started with a good starter even with low compression.
You can go to an auto parts store and get a compression checker for around $25

pfact

My Feedback: (92)

Soarrich & Dirtybird,

Mike Dooley from RC Showcase called me on Wednesday. When he returned the engine to me last month he included a new ignition module which required a different timing setting than I had. Per his instructions I moved the hall sensor all the way to my right but nothing was different - not even a pop. Mike is sending me a new ignition to try, he had no other ideas of what could be going on.

I don't have a compression gauge for a gasser but I can tell you that flipping the prop is a test of shoulder strength - compression has to be good. The oft offered addage "all you need is air, fuel, and spark" is a simplification that belies the complexities of auto advancing electronic ignitions and Walbro carbs. This is a great case in point - I get a nice bright spark from both plugs with every rotation of the prop and the crank case is wet with gas. I recently had a similar problem with a DA 150 that wouldn't start - it turned out to be a frayed wire from the Hall sensor that even DA missed.

Our flying time is very limited, my Son and I get to the flying field only 6-8 times each year, being grounded by a reluctant engine takes a big toll on our flying. I will try the new ignition, if it doesn't work I have decided to add my name to the list for a new 3W 210 and will shelve the ZDZ.

Phil

Thunderbolt47

My Feedback: (8)

Why was the carb inverted?

pfact

My Feedback: (92)

Thunderbolt57,

The carb needs to be inverted to fit into the C-ARF 3.3M Yak so that the choke and throttle control arms fit under the horizontal tray in the front of the plane. Mike Dooley kindly did it for me. It required drilling a new hole in the phenolic mount the carb attaches to.

Phil

dirtybird

My Feedback: (5)

"all you need is air, fuel, and spark" is a simplification that belies the complexities of auto advancing electronic ignitions and Walbro carbs"

If you put fuel in the spark plug holes you have eliminated the carbs.
You can check the timing by removing the plugs and see where it fires in relation to tdc. See CH ignitions instructions. Call RCS and ask them where it should be.
The ZDZ is a good engine. If you have trouble with it the odds are you will have trouble with a 3W

pfact

My Feedback: (92)

Some follow up.

We finally got the engine to start, or at least sometimes we get it to start.

Mike Dooley sent us a new ignition and had us change the timing to accommodate it - no luck. We changed the plug on the ignition and removed the velocity stack, again no luck. Finally, Mike sent us a new carb. While installing it I noted that the carb gasket was torn and there was no sealant between the phenolic plate and the carb. After carefully reseating the gasket we finally got it to start up.

But .... starting it is a nightmare. The ZDZ "5-5-1 flips" method doesn't work, instead we need to flip it 20+ times until fuel drips from the choke plate before it goes. Mike suggested richening the low needle which at 2.5 turns out hasn't made a difference. Moving the timing to about 9mm helps a bit but its too difficult to start to make it worth taking to the flying field.

Any thoughts on why its so hard to start?

Phil

Zeeb

My Feedback: (41)

Well Dick Hanson is the ZDZ guru and I don't pretend to know what he does about them, but I will tell you that you must make sure the choke plate is closing completely. I don't have any experience with the 210, but on all of my ZDZ's they don't like to start unless they are wet when cold.

First start of the day I open the throttle all the way and close the choke. Then flip about ten times as I run my dry after each flying day and they seem to pull fuel from the tank faster with the throttle open. Then I close the throttle and flip until I hear the "snotty nose" sound, usually about 3 more flips. Then it's choke off, ignition on and with the throttle cracked they'll ususally start on the next flip. Much easier after having been run and fuel is already at the carb, but that first one it has to be wet. Now it is possible to flood a ZDZ although it's not easy.

You might try what I call the DA method of flipping it over with the choke and ignition on until it pops to verify there is fuel in the engine, but in my experience that usually floods them and it'll take another 8 to 10 flips to get 'em going.

After mine have been started the first time of the day, I can usually get them going on subsequent flights in just 1 or 2 flips.

JoeAirPort

My Feedback: (41)

I had the same problem with my 50 NG but I did finally figure it out.

Basically mine needed the choke cracked open to stay running right after a start. After a few seconds I could open the choke and it would stay running. It just seems like with a properly leaned low needle they needed lots of priming to get the juices flowing through the rotary valve, crank case, and cylinder. I have two 50NG's and they both were identical with this behavior. I can get them both started with very little effort now. It took me a while to learn the engine. But wow how sweet is the midrange on these. Very fast transition too.

Not saying you don't have a problem engine there....I'm just saying what I did to get mine started an running. The engine's vacuum is responsible for sucking in the fuel and air. If there's a leak somewhere it would certainly not draw the mixture very well.

Hope you get it running. Supposed to be a great engine.

pfact

My Feedback: (92)

Thanks guys.

A "DA" starting method is the only way we can get it running. Using the ZDZ method we get a couple of pops but it won't fire up ... and we only get 1 start, it won't restart. From what I can tell, there is no way to flood these engines, I think our primary problem is getting fuel to the cylinders.

Phil

Zeeb

My Feedback: (41)

Well that sounds like you've got a better handle on things, I think from your comments that checking for the choke plate closing should be high on your list. As Joe noted, mine are a bit cold blooded when first started and the low needle setting is responsible for that as if it's set for a really clean mid-range it's a bit too lean for a start. I used the partial choke method on my ZDZ-100 when I had a radio where I setup the choke on a dial. Now I just run 'em a bit richer on the low speed needle and let them warm up a bit before trying to rev them up.

I kind of scanned over the thread again and I don't see any reference to this possible problem so I'll mention it if you've removed the idle screw stuff as most of us do, it is possible to get the throttle plate rotating in the wrong direction. If that's the case, you'll have real problems as it doesn't pull fuel like it's supposed to through the low speed ports in the carb barrel. It's also kind of a common issue with ZDZ's from what I've seen posted and Dick has made mention of it on more than one occasion.

When the throttle is closed the head of the screw holding the plate to the shaft should be pointed toward the engine. The screw head on the choke plate should be pointed away from the engine.

dirtybird

My Feedback: (5)

Yes that happened to me with my ZDZ80. It would start with the throttle wide open but as soon as you tried to close the throttle it would quit. Its a common mistake as to open the throttle you turn it CCW when viewed from above the throttle arm. Thats just the oposite of what you might think.

JoeAirPort

My Feedback: (41)

Also you should here a shwishy sound in your cylinders if they have fuel in them. I'd keep priming with full choke and WOT until I heard that sound loud and clear. The reason why DA's method works and the ZDZ doesn't is because you need more than 5 flips to prime. DA's method is to keep flipping till it pops, may take more than 5. May take 20 depending on how far the fuel is away from the engine and also the engine's vacuum, the choke plate seal, leaks in the crank or carb...etc.