ww2birds

My Feedback: (14)

Hi Guys,

I've been searching some of the RCU history for instances of a low-end needle whose threads appear to be loose. I have a 3W 80 that has proven very difficult to get a proper idle tuning. I believe it's a Tillotson carb.

I have many 3W (and others...) engines, and have never had a problem like this. When inspecting the needles to make sure I knew how far out from "0" I was (this is hard to see, since this is a rear induction motor in a warbird), I noted that even at about 1 turn out, the low-end needle is quite loose in its threads .. easily wiggles back and forth.

I can't imagine this is normal .. seems that air would leak by, perhaps causing the erractic idle issues I am having. I've seen some threads that talk about using teflon tape on the threads, and fretting about teflon slivers getting into the motor.

Do any of you know how the LE needle is supposed to seal? Perhaps an o-ring deep inside that has gone bad? Some sort of "goo" on the threads?

Advice is welcome!

Other than this issue, the engine runs beautifully at mid and high throttle .. and even sometime at idle .. but it's the "non-sometimes" that are driving me batty...

Dave McQ

bob_nj

My Feedback: (62)

Parts explosions are available, however you need to positively identify the carb first.

ww2birds

My Feedback: (14)

I have it out of the plane now, I'll get the specifics posted later tonight. Thanks

bubbagates

My Feedback: (32)

one of the first things I do on 3W (tillison carbs) is to cut the needles down. Not the point itself but the end where the screwdriver goes. Since they are so long and somewhat heavy the vibrations alone tend to loosen them up and also change the settings. I've run into the same thing you have and it's almost always the threads have become damaged. I'd have to look and see but I do not think there is any o-rings to replace.

I'll have a look and report back shortly

Nogyro

My Feedback: (10)

No o-rings on the needles of the 3w-80........At least not on mine.

Riverdancer

My Feedback: (5)

Hey there ww2birds..

I have the same trouble with my 75, recomendation was to shorten the needs and strech the spring a bit.. Min would go rich in the air after about a minute of flying. Check the low needle on the landing and it backed out 3/4ths of a turn.. [X(]

I am hoping to try mine again this week end..

Please let me know how you made out.

Riverdancer

Flyin Woodbutcher

My Feedback: (3)

A little dab of blue lock-tite will seal the neddle and hold it still.

FWB

bubbagates

My Feedback: (32)

Hey Kent, how ya doin? Looking forward to another Butcherfest and Vinny told me to say Hi. Are ou guys gonna do another judging seminar at your place again next year. I'd like to come to it if you do and I can probably talk Vinny into coming along with little trouble

Anyway, won't the locktite break down after a while and possible get into the carb? I've always had good luck just trimming the screwdriver end of the needle to keep it from vibrating

Tony Hallo

I had the same problem on my ZDZ80, RC Showcase recommends cutting the needles down and resloting, I replaced my with a Walbro, problem solved.

Flyin Woodbutcher

My Feedback: (3)

Hey Bill , same ole stuff, flyin to much. Yes to all the ?s . .Imac boot camp, juding seminar and Butcherfest.

The DA fiddy comes with lock-tite on the neddles. I have bout 10 gals through one and no problems. Should not take much to hold the neddlw still.

FWB

bubbagates

My Feedback: (32)

Cool on the IMAC stuff and I'll give the locktite a try should I need to do it again.