I am starting to have a problem with my carb sticking on very high idle. Had 3 beautiful flights on my new Taurus powered Pitts. On 4th flight I just about didn't get it to idle down for landing. I noticed there is some play on the throttle of the carb where the spring is. Should this spring be removed to keep it from having tension on the throttle sleeve? Will it cause a problem if I do?
dp

alot of people remove it and have no problems at all.if you have play in the linkage then i would fix it and remove the spring.i left mine on for saftey if the linkage fails but i use missing links so i have no play at all

jetjockyf, do you have the Taurus 3.2 on your pitts?. If so, how does it fly and Bill O. does not recommend removing the spring. Personally I don't think it is necessary. According to some..the spring keeps the shaft from wearing out the carb body. I'm not sure I agree with that but some people believe it to be true. Taking the spring off won't change your idle, your throttle linkage is responsible for that. Make sure it is 100% positive in the open and closed position.
I have 10 years in the Chain saw industry in my past if that means anything.. Regards BobH.

Bob, the Pitts flies super with the Taurus 3.2. Got better on each flight. Fourth flight though is when the idle would stick at about 3000 rpm. Could "goose" the throttle and sometimes the idle would return to low. Servo linkage is fine, no binding.
Ran some tests this afternoon to try to find out why the problem. Disconnecting the servo linkage from the throttle and with the cowl off, I would start the engine and manually move the throttle until it stuck on high. I could reach on the front side of carb (engine is inverted and "front" is toward the prop) and finally figured out if I pulled or pushed the butterfly lever where the spring is toward the spring it would compress the spring about 1/32", free up the other side of the linkage where the nylon arm is attached with a set screw and allow the idle to go down to where the engine would almost cut off. Do I need to put a washer or spacer to keep the spring compressed if I don't take it off?
I am chomping at the bit to fly this bird some more, but I will end up with a damaged plane if I keep having this problem.
dp

The spring is there for 2 reasons, to bring the throttle back to idle on the chainsaw and to keep the throttle disc centered in the venturi..If you take the spring completely off the throttle disc will vibrate in the bore at high rpm and wear it out, along with the carb body itself...Extreme wear will result in enough space around the disc to let fuel in when the throttle is closed, so the idle will be higher than it should be...The spring should be left in place but if you don't want the tension the ends can be clipped off..That way the spring will still keep the disc centered but will not put a load on the servo...There is a clip on the opposite end of the throttle shaft that the spring keeps tension on to keep the disc in the middle....

jetjockyf18, Is it possible that the butterfly is hanging up in the body of the carb and when you move it to the side that it becomes unstuck? I can't see why the spring by itself is causing the problem? BTW how does the Pitts land with that engine? I am looking the Eagle for this Taurus Engine. It's supposed to be for my Yellow P-47 Jug but that project is on hold for the moment. I am finishing a Duncan Hutson SE5a for the Scale Masters next year lol!.. BobH.

Rcign1 is right do not remove the spring. You can eather clip the spring where it hooks around the arm or slip it off the arm so if you want to reattch it to the arm if you ever need to.

Bob,
The Pitts lands great with this engine considering I only have 4 flights and 4 landings!
That's what I am wanting to get some practice on as a full stall 3 pt. is what it likes best. No tail high 2 wheel landing here, wants to bounce too much!
dave

jetjocky, thanks!! I have flown that plane with a zdz 50 and its pretty quick. It was not my plane so I did not land it. We have 3 of them flying at our field, one has the zdz 50, one a G-62 and the last a 4 cylinder OS FS. All three fly well but they seem to need some speed on landing or..?.. Thanks again BobH.

Bob,
Yes, I did have to keep the speed up on landing. Had one dead stick which caused me to land off the runway with some minor damage.
From your previous reply, it probably is possible that the butterfly might be hanging up inside the carb, and pushing the throttle rod is releasing it. I did not mean to imply that I thought the spring was the culprit but only acted to keep tension on the rod. Do you or anyone else have a solution if this is the case? Bill O. from Taurus suggested a nylon washer on the opposite side of the rod to be placed underneath nylon arm which is attached by the setscrew.
Bob,I also have one of the Yellow Jugs awaiting construction. Thinking about using this same engine on it.
JJ

I agree with Walton, just slip the end of the spring off the arm. The spring still keeps the play out of the shaft but does not impede the movement of the throttle.

It's not the spring arm on the throttle that is causing my problem. I realize it helps return the throttle to idle or off when it is attached. If I take the spring arm off, still leaving it attached on the shaft, the throttle is then free. Only the servo then is responsible for closing the throttle since that tension is gone. But, the thickness of the spring on the shaft is what is holding the throttle rod and lever away from the carb body. If you put your thumb on the left side of the shaft (where my servo linkage is attached) and your index finger on the spring side, you can move it back and forth about 1/8 inch. When my engine sticks on high idle during my tests, I can push the rt. end of the shaft toward the carb which compresses the spring (which is now not attached to the lever but still on the shaft) and frees up the sticking and the throttle returns to normal idle. Should I install a nylon washer on the left side opposite the spring to keep the shaft shifted to the left? That is my question.

The answer is no...Unless it's put together wrong the throttle shaft has a clip or washer on the end opposite the lever that connects to the throttle servo....The spring goes under the lever and keeps the shaft against the clip..If the disc is not centered when the clip is against the carb body it should be loosened up and re centered...The spring will then keep it on the middle....[8D]