TT39 Needle Settings
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From: fernandina, FL
I have what seems to be the usual question in regard to the TT39, What are your high and low speed needle settings. I have done a search in several places but heve yet to see a consistent reply as to what the factory low speed needle setting is. The range seems to be 1.5 to 4.0 turns. Does anyone have a fresh fractory carb that they could check the low speed setting? Any help would be greatly appreciated.
gg
gg
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From: fernandina, FL
Anyone? The motor will idle but it seems to go lean crossing low to high RPM. I live at sea-level and may have to run leaner than you high altitude guys. Any help would be appreciated.
Thanks,
gg
Thanks,
gg
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From:
on my TT39, the high needle is about 2.75+ and
the low needle is close to whatever it was
at the factory.
It doesn't really matter what the rest of us
use. You need to be able to tune the engine
correctly. Set the high to almost 3 turns
from closed. It should idle and it should be
flyable. Once the engine is warmed up,
pinch the fuel line near the engine inlet
and start counting. You should be able to get
to about 3 or 4 before it starts speeding up
and then a moment after that, it'll die. Thats
a good starting point for the low needle. If it
speeds up immediately, richen the low end
and if it takes 5+, lean the low a little.
Then start doing some full power climbs and
see how the high needle is. You probably do
not want to go below 2 5/8 turns cause that'll
be too lean. Now go back and check the low
again annd re-adjust.
the low needle is close to whatever it was
at the factory.
It doesn't really matter what the rest of us
use. You need to be able to tune the engine
correctly. Set the high to almost 3 turns
from closed. It should idle and it should be
flyable. Once the engine is warmed up,
pinch the fuel line near the engine inlet
and start counting. You should be able to get
to about 3 or 4 before it starts speeding up
and then a moment after that, it'll die. Thats
a good starting point for the low needle. If it
speeds up immediately, richen the low end
and if it takes 5+, lean the low a little.
Then start doing some full power climbs and
see how the high needle is. You probably do
not want to go below 2 5/8 turns cause that'll
be too lean. Now go back and check the low
again annd re-adjust.



