Zdz40rv-l
04-19-2003, 09:59 PM
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Zdz40rv-l
I have a few problems with my ZDZ40RV-L. I bought this engine used, but it looks to have very little run time. The seller had just gotten a Walbro carburetor in place of the Bing before shipping it to me, and the carburetor was mounted when I got the engine. I have the engine in a DiablotinXL swinging a MenzS22x8 and running the Diabltin header and muffler can. The engine will try to run on the choke on the third flip or so, then with choke off and throttle at idle, it will start on the third - fifth flip. It will run for a few seconds and die, or it will run, but not take the throttle very well. Some times it will run and after a little warm up will take the throttle well, but then when left idling (high idle) for some time, it will sputter and will not take the throttle and dies. I kept trying to start it today at the field, and it would start, then cut out and die. It seemed as the cutting could be ignition related, because it was rather sudden and without hesitation. I have kept trying to richen up the idlle, but to no awail. I have both needles at about 2.5 turns out, the low end some times more.
What's the plug gap supposed to be? I could start with that and see if a slight change helps. I am running a 4 cell 1650 mAh NMHi batter on ignition with good charge.
DKjens
What's the plug gap supposed to be? I could start with that and see if a slight change helps. I am running a 4 cell 1650 mAh NMHi batter on ignition with good charge.
DKjens
04-20-2003, 12:36 AM
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Zdz40rv-l
Possibly -, the Walbro -which has a different location for the pressure tap --- is not getting --OR is leaking the pulse from the engine.
The conversion from Bing to Walbro required either a different location for the pulse (an ne hole drilled in the backplate -- OR an adapter which makes a proper , not leaking passage.
If the conversion was not done by RCS- --ASK the seller, who did what.
The conversion from Bing to Walbro required either a different location for the pulse (an ne hole drilled in the backplate -- OR an adapter which makes a proper , not leaking passage.
If the conversion was not done by RCS- --ASK the seller, who did what.
04-20-2003, 08:40 PM
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Zdz40rv-l
dick,
I just removed the engine and took the carburetor off. It looks to me like the carb. was mounted 180 degrees off. It was mounted so that fuel inlet on carb. was towards cylinder head. The engine case has the pulse hole and a slot, then there is a phenolic spacer/gasket, and old hole has been plugged, then there is another nylon phenolic spacer and then the gasket. Looks like the carb was mounted so that the hole to the pump (the side of the carb where the "Walbro" name is) was 180 degrees off the side with the pulse hole. I will reassemble and check for fuel draw before re mounting on plane.
I will also check my used zdz 60 and 80 before mounting on planes, since now I have to redo throttle and choke linkage.
DKjens
Whoops, it didn't work. I took the gasket off the nylon spacer and saw the channel/groove. Lokks like the gasket was on there wrong, turned carb around as before, mounted the two spacers and the gasket correctly, checked and it is drawing fuel. I will remount engine and check the running.
DKjens
Well, just ran the engine again. Carb definetely draws fuel, coughs on 2-3 flips with choke on, starts on 5-7 flips after that. Still acts like running lean on low end, despite having had low needle almost of the carb. I figured, maybe since it's a brand new carb it will need som fuel through it, so got it running at high idle 2k, would hesitate to take throttle, but if slowly advancing would overcome it and turn 6k on rich high end. I ran some 5-6 oz through it like this, and it would be a bear to start if shutting it down, needed starter. It would cough alright with choke on, but wouldn't start by hand. Should I try to run more fuel through it, or send it in to Mike? I'll see what Mike says tomorrow, maybe. I was careful not to overtighten the carb when reassembling, so hope there's no leak there.
DKjens
Spoke to Mike this morning. He agreed it sounds like a carb. fuel problem, so he is sending me another carburetor to try. He is shipping it three day, so I'll be able to have it ready for next weekend. I love doing business, and the subsequent support, from RCShowcase.
DKjens
I just removed the engine and took the carburetor off. It looks to me like the carb. was mounted 180 degrees off. It was mounted so that fuel inlet on carb. was towards cylinder head. The engine case has the pulse hole and a slot, then there is a phenolic spacer/gasket, and old hole has been plugged, then there is another nylon phenolic spacer and then the gasket. Looks like the carb was mounted so that the hole to the pump (the side of the carb where the "Walbro" name is) was 180 degrees off the side with the pulse hole. I will reassemble and check for fuel draw before re mounting on plane.
I will also check my used zdz 60 and 80 before mounting on planes, since now I have to redo throttle and choke linkage.
DKjens
Whoops, it didn't work. I took the gasket off the nylon spacer and saw the channel/groove. Lokks like the gasket was on there wrong, turned carb around as before, mounted the two spacers and the gasket correctly, checked and it is drawing fuel. I will remount engine and check the running.
DKjens
Well, just ran the engine again. Carb definetely draws fuel, coughs on 2-3 flips with choke on, starts on 5-7 flips after that. Still acts like running lean on low end, despite having had low needle almost of the carb. I figured, maybe since it's a brand new carb it will need som fuel through it, so got it running at high idle 2k, would hesitate to take throttle, but if slowly advancing would overcome it and turn 6k on rich high end. I ran some 5-6 oz through it like this, and it would be a bear to start if shutting it down, needed starter. It would cough alright with choke on, but wouldn't start by hand. Should I try to run more fuel through it, or send it in to Mike? I'll see what Mike says tomorrow, maybe. I was careful not to overtighten the carb when reassembling, so hope there's no leak there.
DKjens
Spoke to Mike this morning. He agreed it sounds like a carb. fuel problem, so he is sending me another carburetor to try. He is shipping it three day, so I'll be able to have it ready for next weekend. I love doing business, and the subsequent support, from RCShowcase.
DKjens
04-22-2003, 05:12 PM
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Zdz40rv-l
There was a problem with the carbs not drawing enough fuel on the zdz 40 . I'm surprised mike didn't mention this to you. They had a website showing directions on how to disassemble the carb and make a slight adjustment to bring up the fuel flow.
I also was sent out a new carb which acted even worse so i reinstalled the old one and performed the minor fix wich made it possible to set the low end and high end needles to approximately 1.5 out .
engine know runs OK.
just have to fix a problem with airflow in the cowl disturbing carburetor mixture in flight.
I also was sent out a new carb which acted even worse so i reinstalled the old one and performed the minor fix wich made it possible to set the low end and high end needles to approximately 1.5 out .
engine know runs OK.
just have to fix a problem with airflow in the cowl disturbing carburetor mixture in flight.
04-22-2003, 05:22 PM
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The Walbro WT-76 carbs are more than adequate. The fix pertains ONLY to the 40B reed valve engine at this time. If you performed the fix and it works great, then that is fantastic.
Thanks,
Mike Dooley
RC Showcase
Thanks,
Mike Dooley
RC Showcase
04-27-2003, 02:41 AM
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Update!!!!!
Well, it has been one hecl of a hellish week at work for me, home late every evening. Friday came by, no carb., I called Mike, it had been sent ground, and I won't get it til Monday. I wasn't going to let a weekend go by without trying something, so Friday after coming home, I was able to remove the carb. from engine with engine in plane. I removed the cover and the diaphragm and bent the little doohicky lever in the middle up as close to .030" as I could judge. I can see by how it works, that the mod. will open the valve earlier and allow more fuel. I went to the field this morning, assembled the plane, set both needles at 1.5 turn out, and the engine started right up, took the gas well, super low idle. I had three great flights with the DiablotinXL/ZDZ40RV-L and I love this plane. First time out and I hovered, flat spinning, knife edge, waterfalled, and best of all, elevators and harriers are great with this plane. Although I have CG about 1/2" behind recommended, it can go further back. I am selling all my glow stuff, no more using half roll of tissue paper to wipe down plane after a day of flying.
DKjens
DKjens
04-28-2003, 11:54 PM
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Zdz40rv-l
Good to here you were able to work out the carb problem. Did you say you had a regular zdz 40 or the 40b in your diabolitan. I thought only the 40b carb(wt-76) had a fuel draw issue.
