|
DA 50 Running Problems
I am having problems with my DA 50 and looking for help. It has been running fine for about three years with no problems. At the end of last season it began to have problems sputtering on the high end. I sent it back to DA for service and they updated several items on the engine. I just placed it in a Yak 54 with the DA tuned pipe. I was able to get the engine adjusted to a smooth idle and transition; however, when at full throttle it would not run consistently. It acted like it was too lean so I continued to richen the high end. It improved but I ended up eventually backing the high end screw completely out and it still continued to act this way. I never had any problems until now and am looking for some help. I called DA and they said it sounded like fuel draw issues; however, I am using the same 1/8 ID fule tube that I have for the past three years.
The engine was completely reconditioned by DA and this was the first time out of the box. It has a new ignition, plug, DA updates, etc. I checked the fule with a friend flying who had no problems to help narrow down the possibilities. Any suggestions on why it would sag and then begin to surge at full throttle? |
RE: DA 50 Running Problems
call DA--
the DA pipe (what is that?) can be one of many -also if the (?) pipe is setup incorrectly it may not want to run at full rev-if th prop is a mismatch in load . there are many pipes and cans and headers etc., and judging on the number of comments here on this type of problem--I would gues that the combo you have is not matched. The engine will run as strong as any 50 -if the exhaust is matched to the prop LOAD (forget size) on the outside chance there is a carb problem -- first get the prop to YOUR exhaust setup sorted out - then make carb fixes as may be needed. |
RE: DA 50 Running Problems
Thanks for the advice. DA sent me the tuned pipe matched to the engine and 23 x 8 prop. When I flew pattern plans a long time ago, adjusting the pipe was a huge issue. My understanding with DA is that they already have the pipe matched for the engine. Any other thoughts?
|
RE: DA 50 Running Problems
put on a smaller prop before you do anything else -a 22.8-
If it then runs correctly -or much better -you likely have the combo mismatched . On the pattern planes -exactly the same issue existed. the info on pipe tuning was from racing guys and TOTALLY incorrect for our uses. I flew piped pattern planes also -in70's -80's etc. peaky setups unless running at full tilt . lots of power tho - the DA50 will turn a 23x8 very nicely on matched pipe setups -- seen it . |
RE: DA 50 Running Problems
Chris,
I would double check your fuel system... Tank, lines, filters, T's... etc.. It does sound like a fuel draw issue.. If DA replaced your piston ring, you will need to break in the engine, again... with a good 22x8 prop. I have been thinking about a tuned can for my DA50, so keep us informed on what you find out. Dennis |
RE: DA 50 Running Problems
ORIGINAL: chris monroe I am having problems with my DA 50 and looking for help. It has been running fine for about three years with no problems. At the end of last season it began to have problems sputtering on the high end. I sent it back to DA for service and they updated several items on the engine. I just placed it in a Yak 54 with the DA tuned pipe. I was able to get the engine adjusted to a smooth idle and transition; however, when at full throttle it would not run consistently. It acted like it was too lean so I continued to richen the high end. It improved but I ended up eventually backing the high end screw completely out and it still continued to act this way. I never had any problems until now and am looking for some help. I called DA and they said it sounded like fuel draw issues; however, I am using the same 1/8 ID fule tube that I have for the past three years. The engine was completely reconditioned by DA and this was the first time out of the box. It has a new ignition, plug, DA updates, etc. I checked the fule with a friend flying who had no problems to help narrow down the possibilities. Any suggestions on why it would sag and then begin to surge at full throttle? Read through these forums. The rumor is -- that carb is too small for the DA50 and won't pass enough fuel to actually make the engine rich on the high end. You already know this -- you've backed the high speed needle all the way out and still too lean. You've put a pipe on it and thats going to use more fuel. More power = more fuel comsumption. You'll NEVER get the carb rich enough to feed that engine with a pipe on it. IMO it's obviously lean. But, the problem is--no amount of fussing with it will ever fix the problem. You need to find out what carb the other guys have put on this engine as a replacement. Buy one of those and install it on your engine. |
RE: DA 50 Running Problems
strange -I run both the wt76 and the 201 carbs on my zdz50's with pipes -turn 22x8 props over 8400 in the air no lean problems
and no heating problems .why should the DA 50 go lean with these carbs -unless there is a isolated carb problem. ? the 201 has 3 primary discharges and a high speed outlet the WT76 has one each - but the high end adjustment seems much the same on both - I have run a number of both -and prefer the 201 as it typically is easier priming and has a great low mid speed control . There is a HD carb also which fits and runs very well -I got one of these from RCI a while back when testing stuff -it has more bore -but fit and ran same power levels etc.. |
RE: DA 50 Running Problems
I had two DA50's, and here at 530 ASL I couldn't get the HS needle to let enough fuel in to get the engine to drop 100 rpm on the rich side using 50:1 oil, and the LS needle set properly......Put a WT 76 on them and I could drop the rpm's 500 or more if I wanted.....The only way I could get them rich at WOT was to open the LS needle till it burbled real bad. Then that compensated for the lack of fuel on the high side.....
chris may very well have a mis matched header/prop combo, but he may also be just starving for fuel at WOT.......Try opening the L & H needles 2 1/2 turns and see what happens....It may be extremely rich at idle, but that will let more fuel through at WOT. |
RE: DA 50 Running Problems
ORIGINAL: dick Hanson strange -I run both the wt76 and the 201 carbs on my zdz50's with pipes -turn 22x8 props over 8400 in the air no lean problems and no heating problems .why should the DA 50 go lean with these carbs -unless there is a isolated carb problem. ? the 201 has 3 primary discharges and a high speed outlet the WT76 has one each - but the high end adjustment seems much the same on both - I have run a number of both -and prefer the 201 as it typically is easier priming and has a great low mid speed control . There is a HD carb also which fits and runs very well -I got one of these from RCI a while back when testing stuff -it has more bore -but fit and ran same power levels etc.. Not everyone has the ability to diagnose problems or fix them as well as you. I think it's entirely possible that he may not be getting enough fuel at WOT with the stock carb. |
RE: DA 50 Running Problems
possible -but probable?
the carb is designed for a basic swept displacement crankcase --as such -if it is reasonably well matched --the RELATIVE fuel air ratio should work throughout entire power band In this case - I would have slightly closed choke plate to see if the mix goes rich- it should . I don't know if there is a particular restrictive setup in the high speed discharge port - simply becuse I have never seen a problem with flow. If someone knows a big deeply held secret aboout how this particular model carb runs lean at high speed -or was calibrated to run lean (restricted flow thru main)- speak up . I would like to know . I guess the ones I have were sneakily modified by ZDZ? I don't think so -- |
RE: DA 50 Running Problems
I wonder how many DA 50´s are out there 6000, 7000.... More. I don´t think you can sell that amount of engines with a missmatched carb....
I was thinking I had this same problem with my DA 50 (not able to go rich in the high end) but it turned out that was more a tuning problem than anything else. The carb supplied with the engine supplies enough fuel at high throttle settings and the transition is very good.. at least in my case. It is also true that while the carb supplies enough fuel you cannot get this engine overly rich like you can do with other engines and I wonder if there is a reason for DA to keep it that way. It is extremely unlikely that they would not be aware of a problem like this after selling so many engines and considering that fixing this condition is very easy. If there was a problem they would have fixed it by now. Andres |
RE: DA 50 Running Problems
I have used WT76 carbs, and 201 carbs on my DA50... Top end rpm's don't change, but the low end is much better with the WT76. I'm using a Slimline wrap around pitts... restrictive somewhat...
And yes I have a little burble at 1/4 stick. No problems, the engine is still quite responsive, and powerful. |
RE: DA 50 Running Problems
There is a HD carb also which fits and runs very well -I got one of these from RCI a while back when testing stuff -it has more bore -but fit and ran same power levels etc.. Believe it or not, but the DL50 (the good one, not the clogged one) carb works well on a DA50... |
RE: DA 50 Running Problems
ORIGINAL: dick Hanson possible -but probable? the carb is designed for a basic swept displacement crankcase --as such -if it is reasonably well matched --the RELATIVE fuel air ratio should work throughout entire power band In this case - I would have slightly closed choke plate to see if the mix goes rich- it should . I don't know if there is a particular restrictive setup in the high speed discharge port - simply becuse I have never seen a problem with flow. If someone knows a big deeply held secret aboout how this particular model carb runs lean at high speed -or was calibrated to run lean (restricted flow thru main)- speak up . I would like to know . I guess the ones I have were sneakily modified by ZDZ? I don't think so -- Kevin |
RE: DA 50 Running Problems
What happens when the reeds open :
the low pressure created which opens the reeds creates a low pressure in the carb . the carb determines the mix (ratio of air to liquid gasoline ) IF--the reed opening time is short or long - the carb does not know or care - IF------ the low pressure (signal)is very strong or weak - the carb does care . reed stiffness will affect power available but the fuel to air mixture should not be affected.an overly strong low pressure (signal) should increase fuel flow but that would indicate that the carb size (basic venturii size) is too small. So far --I can't find any real difference in top end needle settings of 201/76 -which would indicate that they both flow the same . The 201 will choke more easily than the 76-at least on the ZDZ40/40 engines and it has more dischage orifices (3 vs 1) for low and you could say midrange flow. IF there is any real difference it is in the high speed jet and frankly I can't see it if it exists . someone must know if there is a difference in this part -that is my question. the cover plate on the pump side are different we know that - the zdz carb has a drilled tran sfer passage NOT found in the carbs using external pulse line. so I can only note that the low speed delivery on th 201 is different -as a difference between the two carbs . I simply don't know more about what Walbro may/may not have done in the high speed circuit. |
RE: DA 50 Running Problems
All anyone needs to do to find out about Walbros is go to the source, Luis Salas at Walbro in Cass City, MI...The REAL expert...;)
|
RE: DA 50 Running Problems
fair enough - I don't have a problem with these ----in things so I should have stayed out of it
|
RE: DA 50 Running Problems
ORIGINAL: dick Hanson What happens when the reeds open : the low pressure created which opens the reeds creates a low pressure in the carb . the carb determines the mix (ratio of air to liquid gasoline ) IF--the reed opening time is short or long - the carb does not know or care - IF------ the low pressure (signal)is very strong or weak - the carb does care . reed stiffness will affect power available but the fuel to air mixture should not be affected.an overly strong low pressure (signal) should increase fuel flow but that would indicate that the carb size (basic venturii size) is too small. So far --I can't find any real difference in top end needle settings of 201/76 -which would indicate that they both flow the same . The 201 will choke more easily than the 76-at least on the ZDZ40/40 engines and it has more dischage orifices (3 vs 1) for low and you could say midrange flow. IF there is any real difference it is in the high speed jet and frankly I can't see it if it exists . someone must know if there is a difference in this part -that is my question. the cover plate on the pump side are different we know that - the zdz carb has a drilled tran sfer passage NOT found in the carbs using external pulse line. so I can only note that the low speed delivery on th 201 is different -as a difference between the two carbs . I simply don't know more about what Walbro may/may not have done in the high speed circuit. One of the modelers here bolted on a carb from a DL50 to his DA50 and claimed that he could richen up the mixture.....Where as with the stock DA50 carb the mixture couldn't be richened --The venturi on the DL50 carb is slightly smaller, thus allowing a stronger vacuum though the carb---Possibly allowing the engine to draw more fuel from the carb...What are your thoughts on this?? Kevin |
RE: DA 50 Running Problems
yes-that is a logical answer.
to both questions Iam not -a Walbro "expert" . carbs tho , all basically respond to same fixes. |
| All times are GMT -8. The time now is 05:43 PM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.