TPL33

2 days ago I was unable to shut off my engine by sliding the throttle trim lever all the way down. Something must have moved because the flights before I could shut it down in this manner. I'm back into flying after a 23 year absence and use to struggle with setting up the throttle linkages in the past. Can someone post a fool proof way to set up the throttle so the engine can be killed by sliding the trim lever all the down? thanks.

skeeter_ca

What kind of radio are you using. Alot of the modern radios have a kill button that closes the throttle all the way when depressed. If that is not an option you could readjust the throttle trim so it is at it's highest and then you could have alot of movement to shut down the throttle all the way.

skeeter

flyinwalenda

My Feedback: (5)

If you are using a non-computer radio with no travel adjustment,you will have to continue setting it up like you did years ago by using only mechanical adjustments. Depending on the type of engine you should be able to adjust the barrel throttle arm on the carb. When the barrel is halfway open the arm should be at 6 o'clock. The with the throttle trim at half, push the throttle to full open and watch the carb barrel. It should reach full open when the stick is maxed out . Pull the stick slowly back and the barrel should start to close. If not then you need to either shorten the rod or move the clevis to a different hole on the carb or servo arm closer to the center. Once you get full throttle established then move the stick to low throttle and see where the barrel is. You may have the adjust the rod length again and/or move the clevis on one side only (carb end or servo end) until you get the barrel to open a crack at low and to wide open at full with the trim in the middle. It takes a lot of back and forth to get it right. You may have to adjust the arm on the carb or even the servo to get it just right.
If it was working then maybe the jamb nuts are loose on the clevis and the rod turned or the carb or servo arm moved.
If you have a radio with travel/end-point adjustment it's much easier to adjust.

j.duncker

My Feedback: (2)

First of all make sure that your engine will stop when the throttle barrel is closed. I have had a couple that would not once they were run in.

Nxet get your tranny manual out and look to see if you have a shut down or 'kill' option on the throttle set up. Follow the given instructions.

If not then this is how I do it. Set your trim to low and adjust the linkage to give you the completely closed throttle. Check that you can get full throttle without stalling the servo.

Now run the engine and see where the normal idle is on the trim. Pull back to see if it stops.

acerc

Measure the outer most hole on your carb throttle arm, measure the servo arm for the same distance. If a hole on the servo horn does not match up use the short one. Take the servo arm off the servo, turn Tx and set the throttle end points to as low as they will go,turn on the Rx, move the throttle on the radio to the center point including the trim, open the throttle on the carb half way and attach the servo arm to the throttle servo while holding the carb open halfway. From this point you can adjust uor endpoints to obtain a perfect open and closed position. And it should be operating between 80 to 100% throw.
   Good Luck.

rgm762

My Feedback: (4)

this is how I set mine up every time, works great.

http://www.rcuniverse.com/forum/m_83...tm.htm#8375449

Gray Beard

My Feedback: (-1)

As Duncker said, not all of them will shut down, the original Tower two strokes were notorious for this problem, they had an air leaking carb and you could put a finger over the carb and they still ran. I had one SK that had an air leak in the carb hold down insert in the case that would keep running. Easy fix though. I adjust the linkage with my trim set at center so I'm sure I have both high and low trim. I have the throttle set on a three way switch so it has a high/low/kill activation. Most of the new radios have a kill button that closes the throttle. Run your engine at idle and stick a finger over it and make sure the engine will kill. If so your throttle cable may have stretched or moved so the barrel isn't closing all the way.

da Rock

this works every time with current radios. It gives the best control your radio can give.

yatssdaa

you could have alot of movement to shut down the throttle all the way.

Villa

Before computer radios I often thought that setting up the throttle was one of the most difficult things about this hobby. Understanding the geometry of the linkage does help.

da Rock

The best way to start is simple.

Start with the servo centered and it's arm at a right angle to the pushrod
Have the carb intake halfway open and the throttle arm at a right angle to the pushrod.

Connect the pushrod in the outer hole of the throttle arm and a hole on the servo arm that matches.

Work the stick and watch the opening in the carb. Adjust the end points in your radio to suit.