lgodin

I have a zdz80 with walboro carb, about 2 years old with 10-12 gallons ran thru it. My problem is it will not draw fuel for start, the choke is closing all the way....it just will not draw. I check the tank and lines all is good. If I prime the engine by adding fuel to the air intake the engine starts and runs great. Compression is still very good. Do you have any ideas I where I might look? This engine does this cold or warm, but the intial problem started when warm about 2 months ago.

Ben Diss

My Feedback: (23)

I had this once with one of my ZDZ-80's. It turned out that some of the fuel line had hardened and was not completely sealing over the fittings. I replaced a few pieces and added fuel line clamps on all the fittings. This solved it for me.

-Ben

RTK

My Feedback: (1)

If all else fails buy a carb rebuild kit. In time the rubber on the pump side becomes not so rubbery.

dork_blaster

My Feedback: (14)

Had this problem on more than one engine (one of them the ZDZ80). Filter screen inside the carb was clogged. Took the cover plate off and found small bits of whatever plugging it up.

Riverdancer

My Feedback: (5)

Good Day,

I have just finished trouble shooting the carb from He!!.. I have a new but old Brison 4.2... I have been having trouble with since I started flying it.. hard to prime.. going lean.. flaming out.. you name it..the more fuel I put through it the more inconsistent it got.. finally it would not go to full power.


I can suggest a couple of things to check.. One is check the inlet screen for crap as was suggested..the other is to remove the High and low speed needles.. Spray in some WD-40 with the nozzle and make sure there is good flow to the main jet and the idle jets. If you leave all the covers on and spray in the needle holes you will be able to tell if the jets are plugged with out pulling plugs out. ( I don't know what else to call them) There is a last chance filter for the main jet that could be plugged.


I suspect you have a blocked or partially blocked filter Screen! as your engine runs once it gets fuel.. the pump is stronger once it's running..

Hope this helps.

Take Care.. Riverdancer

corsair01

Had the same problem with my 3W50. My problem was that he reed valves weren't fully closed. After replacing them everything worked fine. (3W has a problem with the valves if the engine gets to hot) I don't know if a ZDZ works the same way as a 3W but checking them wouldn't hurt.

dirtybird

My Feedback: (5)

The ZDZ 80 does not have reed valves.
My ZDZ has the Bing carb and takes at least 15 flips with the choke full on and the throttle full open to get it to prime on the first run of the day. If the airplane has not been flown for a few weeks its best to put in a shot of gas in the carb to prime it

backstab

My Feedback: (3)

I have a ZDZ 160 with the same problem exactly. WOuldnt prime but ran perfectly. I took the carb apart and found that the little screen had an opaque substance coating 60% of the screen. I had to hold it up to the light to actually see that it was clogged and you will to. It cant be seen otherwise....it looked perfectly clean. I took the screen out all together (I have a fuel filter elsewhere in the line) and it took 15-20 flips with it choked and throttle open. I had to put a piece of tape over the hole in the choke butterfly to really get the gas coming out the carb. I took the tape off before running of course.

I hope this helps

extraflyer

I had the same problem with my ZDZ40. It would not draw fuel into the carb even after 30-40 flips of the prop. I solved the problem by putting in check valve on my vent line. Now, two or three flips with the ignition on and the engine pops. Then open the choke and about 1/4 throttle(the ZDZ 40 will not start at idle) and about two or three flips and it starts right up. Make sure the check valve is placed so that it will not allow air to flow into the tank. When you want to remove fuel from the tank you will have to temporarily remove the check valve.

Big_Bird

My Feedback: (1)

I had the same problem on my ZDZ80. I was using a servo to operate the choke and lacked a tiny amount closing the choke. After adjusting the throw the choke worked fine. No more problems.