robteecoker

I have a zdz 80 on a hanger 9 cap 232 1/3. The carb sticks into the motor box on front. I have a problem with fuel getting all in the insides of the plane. How do I fix this problem?

Thanks for your help
Robert

Oilsands

I have the same engine in a plane that I bought. It looks as if there has been some slober inside as well (not sure if it was from this engine or another since it looks as if some changes have been made before I bought the plane). I have bought a trumpet that fits on the carb from RCS which they say will keep that from happening. There is also a carb filter that you can get from them as well. One thing with the trumpet (not sure if it will be the same with the filter), but the bolts hit the sides of the trumpet when installing. If you get the trumpet, it should come with slotted bolt holes so that you can get the bolts into the trumpet.

robteecoker

Thanks for the reply. Did the trumpet work? It looks like it will just extend further back into the box and still slober on everything.

LET ME KNOW IF IT WORKS!
Thanks Robert

gapple12

I also have this problem with my ZDZ 80 carb. I tried a rebuild kit and still no change. I noticed when I first choke the engine it sucks a ton of fuel into the carb and a lot of it spills out in to the box. I have been removing my cowl every five flights or so to wipe it out, IT SUCKS!!

Anyways, I ordered a new carb from RC SHOWCASE to see if it fixes this issue. The trumpet will actually help by using that extra fuel as it flows into the trumpet from the carb, if that makes sense. I will let you know what I find out with my new carb. They don't sell the WJ-38 Walbro carb for the ZDZ 80 anymore, they recommended the new WJ-71. Should be here next week.

Drew

robteecoker

Thanks for the help. I can't wait to see what happens with this carb. Please let me know how it turns out.
Thanks Robert

gapple12

Will do......

How old is your carb and engine? Mine is pretty old and sat around for a year or more. You might just have a bad carb. Here is mine.

Drew

robteecoker

I have the blue head 80. I don't know how old mine is but it runs great so I don't think I need a new carb. Maybe it is too rich.

gapple12

What is your low speed set to? Mine is around 1 1/2 out. Will your ZDZ idle low enough to sit still? Mine will not no matter which way I go on the low speed. Most guys I have talked to said just don't mess with that old carb and buy a new one. I have tried everything and was about to buy a DA 85, but figured I would spend $70 on a carb instead of $800 on a new engine. Oh, mine runs great in the higher RPMs also.

robteecoker

I hate to sound so stupid but I purchased it used and the guy said it was tuned perfectly and it is it runs great. To answer your question, yes it will idle down very low. If yours will not idle down you must have to land hauling ass. When you get it to slow down your plane will land like butter. Mine is in a hanger 9 cap 232 and it will slow way down.
No it is not your motor, your carb is junk if you tune it and nothing happens, you will be very happy with the new carb. It will slow down so much you think its going to die and it doesn't it keeps running. Its a great motor. Have you tried the new vess prop yet? If not get one.

gapple12

Well, it slows down just enough to land, but idle is a killer on it. The carb is so touchy that it changes dramatically by turning the needle just a hair. It has been a pain in my a.. for a month now. Hope the new carb brings it back to life because this engine runs great beyond idle.

I have a Vess 26A on my Yak and love it. I want to try a 26B and see if I get a little more top end. Seems like the Vess 26A is all torque.

Drew

robteecoker

Is the 26b higher pitch, I think it will turn less rpm.

gapple12

Not sure. Two of my buddies have the 27B on there DA100's and there speed on those planes is unreal. They never even have to use full throttle. The way Vess describes these A - B - C pitch is a little confusing compared to using real numbers for the pitch. But I have a ton of power with it and the Yak is a rocket out of a hover. The 26A actually performs just like my 3W 26/10 prop. I cant tell a difference.


Drew

robteecoker

Maybe its just in my mind because I have that same 3w26-10 and I thought the vess pulled harder

gapple12

Ether way the Vess is the way to go. If I were you I would order one of those nice trumpets from RC SHOWCASE and should help on the fuel every where. I had another Yak with a ZDZ 40 on it and had the same issue, but not this bad. The Velocity stack I got for it helped a bunch and gave me a little more power. Good luck and I will let you know what I find with the new carb install.

Drew

robteecoker

Thanks

gapple12

Alright........Installed the new carb (WJ-71-1) on my ZDZ 80 and let me tell you, its like night and day. Runs like a new engine. That old carb was trash I guess cause I never would have got it to run this good. Now, the slobber is still an issue. I did figure out that on initial start up when choking the engine, when you get the first pop start on the engine, thats when you see a lot of fuel running out. Since it does this on a brand new carb, I am assuming its ok. After running, no problems. Seems to be only on choke when a ton of fuel spits out. So my fix will be a velocity stack or filter to use that fuel extra fuel. Will fly it this weekend to see results. Engine sounds like it has more power, so I will borrow a tach and check it out.

Drew

rcdoug

My Feedback: (8)

Gentlemen,

The reason you get the spray out of the ZDZ carb is because of the timing overlap. On a reed valved engine, no fuel can get past the reeds. On a ZDZ they use the overlap on the rotary valve to make MUCH more horsepower. A by-product of this is fuel standing off from the carb. If you put a stack on the carb that is long enough, you will contain the spray. An airfilter on top of that is even better. On most of the aircraft I have used ZDZs on, I have isolated the carb from the inside of the A/C with another firewall.
Does anyone still have first start problems with the ZDZ singles? I am working on a priming solution that does not rely on the crankcase vaccume to get fuel to the engine.

Any replies:

[email protected]

Doug Wheeler

gapple12

WOW, finally someone helped us. I appriciate that reply Doug, that makes sense now.

Mine starts every time this way. I put full choke, ignition on, couple clicks up, and flip till it pops. Then choke off and keep flipping. Usually starts after five flips. I do have issues sometimes the second time I start the engine, for instance second flight say 10, to 15 minutes later. I did notice that I don't have to choke it when its that soon for second flight. I guess there is still some fuel in the carb. If there is a lot of members flying and I wait longer, the initial start method works fine. Hope this helps. With my old carb, I always had issues. Thanks again.

Drew

robteecoker

I am going to order a trumpet from rc showcase and I am wondering which one to order. They show two, a black one with a filter and an aluminum one without. which one works best?
Thanks Robert

arobatx

You will lose some performance with the filter installed, best performance is with the plain aluminum one, no filter...sized for your carb of course.

Mike Dooley/RCS

The 5-5-1 ZDZ starting procedure we recommend and has been posted ond various forums ad nauseaum for years works like a charm!

gapple12

Ok, I ordered the Aluminum trumpet from RCSHOWCASE.COM. Got it Friday and spent all weekend trying to make it fit. Anyone have issues with these? I had to reem out the holes larger to fit the screws to the carb, but there is no way to screw them in at that angle. Any ideas??

Bass1

"but there is no way to screw them in at that angle. Any ideas??" I had the same problem on my ZDZ 40. I ended up making a trip to the local "Fastener Warehouse" and bought several different length (shorter) screws. I found a pair that were somewhat shorter (can't remember what length) that worked. The shorter length helped alleviate the sharper angle required to clear the top of the bell on the trumpet. It still took a little finesse to get them in though. Still get the slobber.

Big_Bird

My Feedback: (1)

Robert, here is my solution for the slober problem. I cut a hole in the firewall that would just fit a soft drink aluminum can. I then glued it in with Zap-A-Dap-A-Goo. A small amount of slop collects in the can and most of it evaporates. No slober in the plane.

robteecoker

You must be an engineer, I would have never thought of that. Does the motor run fine like that? How far away is the bottom of the can from the carb? I just bought a velocity stack for it which, they say will make it run better. I would think that the can would cut down on preformance. Does it run the same?