Tuning MDS .68
John Mitchell
through it. I recently crashed the plane it was in and had to shelve it for
2 weekends while rebuilding. I had taken the carb off and the back plate
off to drain the unburned fuel and pour in some Marvel Mistery Oil to
prevent corrosion.
I took it out to the field last weekend and fired it back up. Being
inexperienced I had one of the guys help me adjust the high end needle
valve. I ran the engine until it was hot before adjusting because engine
temp makes a significant difference in the way this engine runs. ( It will
not hand start if hot but will idle nicely when hot.)
It seemed to run okay until the pinch test on the fuel line. It promptly
leaned out and wanted to quit, so he richened the mixture until it wouldn't
quit when pinched. After some slight adjustments and several transistions
from idle to full with the plane on the ground and being held at 45 degrees
it seemed to be running fine. I shut the engine down to wait for a heli to
finish practicing hovering and to cool off in the shade (I live in central
florida and it was high noon and humid).
I went out topped off the fuel and hand started the engine. I ran the
engine slowly up and when it got to ~3/4 throttle it started to cough and
sputter. I backed off to 1/2 throttle and waited for it to warm up. I then
went back to full throttle. Sputter, cough cough, sputter. I tried leaning
it a couple of clicks. Same sputter. I pinched the line and it started to
run fine. I let go. It continued to run fine. I backed the throttle down
and ran it back up. It sputtered until I pinched then it would run fine.
IF you back the throttle down and run it back up within a 3-4 seconds it
will run fine. It does not matter how fast or slowly you increase the
throttle.
Any thoughts or ideas would be appreciated.
Thanks John
Richard George
I am going through the same frustration with a .48 MDS. I haven't figured out
why pinching the fuel line makes it run better until I throttle down to an
Idle. It makes touch and goes rather impossible.
Christopher Hinds
symptoms. Apparently an Enya No.3 Plug and Max 5% Nitro helps greatly as
does 11x7 prop for better flywheel effect.
I say had? Well I am giving up and selling the damn thing!
Chris Hinds
Richard George <alti...@aol.com> wrote in message
news:19990730014301...@ng-cb1.aol.com...
Edwin Smith
problem with his MDS .48. A few days earlier it ran fine strong and no
problems. Then suddenly it was anemic and couldnt get enough speed up to
get airborne then it wouldnt start at all. I gave him one of my glo-plugs
and that got it to start but still wouldnt transition properly. I then cut
a 1/4" piece of fuel line and slipped it over the needle valve. That fixed
it, air leak. Good power and transition and it was back in the air. I
keep idle bar and non-idle bar glo-plugs around just cause some engines can
be finicky about that, no idea why. I dont remember which kind I gave him.
His would glow fine, just wouldnt start anymore.
Edwin
Richard George <alti...@aol.com> wrote in article
<19990730014301...@ng-cb1.aol.com>...
John Crawford
Think of this .... fuel and glow plugs is what makes the engine work
properly ...
Just like a quality set of spark plugs and premium fuel for your own
personnel car helps your car's engine have the performance and economy that
it needs.....
I have found that a high quality fuel in the 15% Nitro range and a OS #5
plug makes a very big difference in the way a lot of these engines run
today. And truthfully speaking I would not settle for nothing less. However,
it might cost a little bit more, but the satisfaction and less aggravation
is what it is all about ....
Some people will try a cheaper way out just to get by and then wonder why
they crashed or damaged their $500.00 model.
My feelings on all of this is ... if I spend the money for that model the
radio gear and engine , why settle for something less on your engine?
Happy Landings!
TexAcoon
www.TexAcoon.com
John Mitchell <jwm...@atlantic.net.nospam> wrote in message
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