ZDZ 80 Manual Choak Question on 330 comp arf

[martin18152]

My ZDZ 80 has a walbro carb, I plan on setting it up with a manual. I don't want to order a ball link from RCS for a strait rod manual choak set up, and I wnat to finish it up this weekend. Any good Ideas on how to make the manual choak? Any common hardware items that can be used? I was thinking of using a glow plane nose weel arm and collar, but I don't have one and would have to buy the whole nose weel assembly to get one, a hardware item would be better. Any good ideas are appreciated.

[Boulder]

I know you don't want to go with a servo, but I use a choke servo on my 80 with a cable and sleeve assembly. The cable runs to a EZ connector on the carb, not a ball link. This assembly took me about an hour to install, including making the tray for the servo, piece of cake.

In my case, the choke rod would have had to be installed inside the fuse, because of the direction of the choke throw. You could try a bell crank assembly, but you would have to install a plate to carry the control behind the motor box.

[Jaybird]

It would be much easier to use a servo. I have set them up with a bellcrank before and it is a real pain. Plus it is nice to choke it from the transmitter. You can solder an arm to a wheel collar to make your choke arm.

[martin18152]

guys, thanks for the input, but I think I got it solved. I installed a nose weel steering arm, had to drill out the collar dia. , the arm seem to slant on a strait shot thugh the engine monunt cone, toward right uper corner of the cowling. I think I can extend the rod out of the cone, between the cowling and cone, and have enough room to reach in the air intake and operate the choak lever, I still have to put the cone on, and cowling to prove this out.

[Jaybird]

Is there any way you could post a pic of the engine install? I'm considering one of these planes with an 80 and I'm curious as to how bad the firewall gets butchered.
Thanks
Brian

[3Dkid330]

I don't know what kind of setup the ZDZ has, but my Dad has one for a DA that consists of a small plastic clevis, a threaded rod, and a piece of Nyrod. Pop the clevis on the choke arm, and the Nyrod attached to the clevis with the threaded rod goes down through a small hole in the cowl leaving about an inch outside. Works pretty well.

Just an idea, I'm not too sure how your carb might be, but if it is like a DA, I think it should work.

B

[Jaybird]

The ZDZ has a rear carb, the choke rod would have to exit the rear of the plane.

[martin18152]

JAYBIRD, I keep meaning to take pictures, haven't taken any yet. I may just take some tonight. I will post them or put a link to my web site. I checked the choak with the cowling on last night, with the prop spiner attached, you can't get your hand in to operate a manual choak; however, I just put a loop in the piano wire that comes through the engine mount cone, and its a simple matter of just usnig a screwdriver to turn the choak on and off. I think it is a simple solution, saves wait, and is easy to operate. I also have a Comp Arf 3.1M Yak, I did go with the servo choak operation with that set up. Comp Arf models have strong fire walls, and cone mounts, you can get away with cutting a bit out. You have to cut out part of the firewall and cone to get the zdz 80 in, and have access to the mixture, and throtle arms, its no big deal. Another decision will be, do you want to put a hole in the top of the cowling, in order to access the mixture controls. As I see it now, every time you want to adjust the mixtures, you will have to remove the spinner, prop, and cowling, once you get the enging tunned in, you don't have to mess with it, unless somthing is wrong. I'm thinking of putting a small hole in the cowl, then covering it up with a sticker later, once the engine is broke in, and tunned.

[dick hanson]

The choke is used a lot - (each flying session) so make a simple plastic bellcrank pull /push.
The mixture controls should never be covered up
this is where burned up/ shi tty running engines come from.
there is NO factory correct mixture and no predictable broken in point to assume correct
True for any engine

[martin18152]

This zdz 80 has power to spare on this model, a little rich won't hurt, factor setting seem to be close on the zdz, not sure about the 80, but the 210 seemed to work out. I usualy monitor the temp, and trade off top end performance if the engine is over power for the plane. I was running the 210 on the yak getting temps from 220 to 230 F, richend up just a hair on the top end, now I get around 190 - 210, don't seem to hear any four cycling in the throttle travel range. Actually I would like to leave the cowling off for awhile, but that might have an affect on the cooling of the engine, well, ducting air and engine cooling is whole other issue.

[dick hanson]

you really ought to find the "four stroke" point- then just barely eliminate it --on th ground
In the air -in level flight a little four strokin hurts nothing as the engine is unloaded in level flight --the correct setting may gurgle a teensy bit
This setting assures enough fuel to cool it on uplines
this is true on any Walbro carb twostroke engines
as for ducting -on any performance twin it is quite necessary unless you are flying in freezing weather
FWIW improper ducting and lean mixes are the major reason for failure on twins
Most mfgrs will not warranty burnt up engines