DA 50 - Carb Behaviour
09-09-2008, 10:05 AM
#1
Senior Member
Thread Starter
Join Date: Jun 2004
Location: Athens, GREECE
Posts: 917
Likes: 0
Received 0 Likes
on
0 Posts
DA 50 - Carb Behaviour
Hi there,
I have been using a DA 50R with a JTEC pitts style muffler on my QQ YAK for some time now.
After some break in procedure in the air and on the ground, I finally managed to adjust the needle settings so that it behaves well even in negative Gs. I use a Menz 22x8 and have installed a carb plate .also use Bel Ray 2% (1/50) H1R synthetic oil.
When the temp is relativelly low the engine seems to work well however when the weather becomes warm it does not run so well in the mid range it starts that nasty two stroke sound sounding a bit rich in the low end which is normal as in high temp air becomes less dense. However I am reluctant to close the low end as I afraid of possible dead stick in negative Gs this has happened once and don't wanna risk it.
Also in the high end even if a turn the needle clockwise about 3/4 to 1 turn from the factory setting, I don't see signifcant change in RPM, the max I have achieved so far is 7200+ but can not get more even if I turn the high needle more. Turning the high end clockwise making it leaner I found that the low end requires to become a bit richer, have you noticed the same?
Do you have any thoughts on the above facts? Any other input or observations from your experience ? It seems that engine can not work well when the temperature is relativelly high and really wonder how the American guys can run these engines in high temp evironments such as Tucson, Arizona etc.
Looking forward to your feedback,
Nikos
I have been using a DA 50R with a JTEC pitts style muffler on my QQ YAK for some time now.
After some break in procedure in the air and on the ground, I finally managed to adjust the needle settings so that it behaves well even in negative Gs. I use a Menz 22x8 and have installed a carb plate .also use Bel Ray 2% (1/50) H1R synthetic oil.
When the temp is relativelly low the engine seems to work well however when the weather becomes warm it does not run so well in the mid range it starts that nasty two stroke sound sounding a bit rich in the low end which is normal as in high temp air becomes less dense. However I am reluctant to close the low end as I afraid of possible dead stick in negative Gs this has happened once and don't wanna risk it.
Also in the high end even if a turn the needle clockwise about 3/4 to 1 turn from the factory setting, I don't see signifcant change in RPM, the max I have achieved so far is 7200+ but can not get more even if I turn the high needle more. Turning the high end clockwise making it leaner I found that the low end requires to become a bit richer, have you noticed the same?
Do you have any thoughts on the above facts? Any other input or observations from your experience ? It seems that engine can not work well when the temperature is relativelly high and really wonder how the American guys can run these engines in high temp evironments such as Tucson, Arizona etc.
Looking forward to your feedback,
Nikos
09-09-2008, 02:09 PM
#2
Senior Member
Join Date: Jan 2002
Location: Arcen, , NETHERLANDS
Posts: 6,571
Likes: 0
Received 2 Likes
on
2 Posts
RE: DA 50 - Carb Behaviour
"warmer = armer"
I know, hat is "Dutch" for you
.
It means, that in hot weather the carb settings must be leaned out and vice versa. If you observe this, you are on the brink of too rich mixture settings. The observation may go away if you lean your idle a tad more, or lean the H-needle a bit more. There is room for experiment. Just be sure to record your current needle settings.
The DA 50 WT201 carb is a bit sensitive to the balance of the low and the high needle. You want to have the low as rich as possible to get a good High needle setting, but not so rich as to get into midrange 4-stroking trouble. So here is the cure:
Adjust the carb when the temp goes up. Hotter (relatively) means less dense air, so richer mixtures, so you have to lean the idle. (idle only please).
I know, hat is "Dutch" for you
.It means, that in hot weather the carb settings must be leaned out and vice versa. If you observe this, you are on the brink of too rich mixture settings. The observation may go away if you lean your idle a tad more, or lean the H-needle a bit more. There is room for experiment. Just be sure to record your current needle settings.
The DA 50 WT201 carb is a bit sensitive to the balance of the low and the high needle. You want to have the low as rich as possible to get a good High needle setting, but not so rich as to get into midrange 4-stroking trouble. So here is the cure:
Adjust the carb when the temp goes up. Hotter (relatively) means less dense air, so richer mixtures, so you have to lean the idle. (idle only please).
09-10-2008, 12:11 PM
#3
Senior Member
My Feedback: (23)
Join Date: Jun 2002
Location: Orlando,
FL
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
RE: DA 50 - Carb Behaviour
Just a thought, consider trying a different prop and even changing props in response to weather conditions. Try a Xoar 23A for the hot weather and a Xoar 23B when it cools off. this is not to say that you don't need to lean out the mid range a bit.
Also, note that changing the low needle will change the high needle setting. Also, if you're tuning seems to be in vein and the needles don't seem to have the effect they should, you may have a clogged port. I was having a heck of a time trying to get my engine to not have a big power spike. I fooled with the needles for weeks. I finally took the carb apart and found that one of the three low ports was clogged with trash. Cleaned out the port and the engine runs like a champ.
Also, note that changing the low needle will change the high needle setting. Also, if you're tuning seems to be in vein and the needles don't seem to have the effect they should, you may have a clogged port. I was having a heck of a time trying to get my engine to not have a big power spike. I fooled with the needles for weeks. I finally took the carb apart and found that one of the three low ports was clogged with trash. Cleaned out the port and the engine runs like a champ.
09-10-2008, 07:38 PM
#5
RE: DA 50 - Carb Behaviour
My DA50 is relatively hard to start after 1st flight. It seems the fuel is not passing through the carb. The cure is either to cool the engine down or to open up 1 turn the low needle and then close it back. Other than that I did not notice performance problem in the air.
When I install WT 201 on my DL50, the same hard-to-start-when-warm problem appears and is fixable with the same tricks. The benefit of using WT201 on DL is that the engine does not burble and runs as good as with the stock carb (wt 889).
Shall36,
How do you clean the ports?
When I install WT 201 on my DL50, the same hard-to-start-when-warm problem appears and is fixable with the same tricks. The benefit of using WT201 on DL is that the engine does not burble and runs as good as with the stock carb (wt 889).
Shall36,
How do you clean the ports?
09-11-2008, 12:05 PM
#6
Senior Member
My Feedback: (23)
Join Date: Jun 2002
Location: Orlando,
FL
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
RE: DA 50 - Carb Behaviour
What I do is dissasemble the carb so that the neopreme parts have been removed. Basically, you'll have the main body sans gaskets, diagraphm, and pump. Remove the needles and spray carb cleaner through them. You can pull out the welsch plugs to better clean the ports, but that's not always necessary. On the low side, you should see carb cleaner spurt out of 3 holes on the WT201. The high side has a single port. In my case, I found carb cleaner only coming out of two ports, so I used compressed air to blow out the ports until I had all 3 working. Do NOT put anything into the jets or ports to clean them out.
