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  #1  
Old 12-12-2012, 07:08 PM
Joe Joe is offline
 
Join Date: Oct 2005
Location: Independence, OR
Posts: 428
Default Throttle Lever Range

Lycoming IO360-M1B with Precision fuel injection servo and Van's "horizontal induction" cowl. "Deluxe" throttle quadrant and standard throttle cable from the finish kit. See the two images below.

Short of drilling a new hole in the throttle lever, is there a way to increase the throttle range? I clocked the lever on the fuel injector servo to allow full (wide open) throttle with the cockpit throttle lever pushed forward. But then pulling the cockpit throttle lever to idle does not allow the fuel servo's arm to contact the idle stop. I can re-clock the lever on the F/I so its arm contacts the stop at idle but then full throttle cannot be reached.

I measured the throttle cable's throw and it's approximately 1.9 inches. The lever arm on the F/I servo requires approx. 2.2 inches of linear travel for full range. Any ideas?

Full throttle:





Throttle at idle:




Thanks,
Joe
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  #2  
Old 12-12-2012, 08:26 PM
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ronschreck ronschreck is offline
 
Join Date: Mar 2006
Location: Gilbert, AZ
Posts: 1,701
Default You have three choices:

1. Drill a new hole in the FI servo throttle arm.
2. Drill a new hole in the throttle lever.
3. Rig up a bellcrank to increase the throw of the throttle cable, like this:



OK, maybe there are more choices but that's the best I can do on short notice.
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  #3  
Old 12-12-2012, 08:48 PM
eddieseve eddieseve is offline
 
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Location: Sydney, Australia
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Default

Hi Joe

I have exactly the same setup as you, same engine, same throttle body and I hate to say it but my supplied parts fit and work correctly.

Are you sure that you don't have any adjustment on the throttle cable itself that will allow you to achieve the full range of throw, check both ends?

Try starting again, put the throttle arm back where it was when you took the throttle body out of the box, undo all the adjustment nuts on your cable at both ends and see how it goes.

Cheers
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  #4  
Old 12-12-2012, 08:49 PM
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jthocker jthocker is offline
 
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Location: Cincinnati, Ohio
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Default

I vote for new hole in servo arm!
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  #5  
Old 12-12-2012, 09:09 PM
Joe Joe is offline
 
Join Date: Oct 2005
Location: Independence, OR
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Well, now I am confused. I'm amazed that yours works, Eddie. In my case, putting the throttle arm back in its original position on the FI servo is not an option: the geometry was totally wrong. The only adjustments on the cable are for position; there is no adjustment for throw. My FI servo body throttle requires 2.2 inches for full travel and the cable only provides 1.9.

Eddie, is it possible that your idle set screw (clearly visible in my second image) is adjusted differently than mine? I'm assuming Lycoming set it when they ran the engine but that may not be a good assumption.

Thanks for weighing in, Ron and Jon. Drilling another hole in the FI throttle arm is beginning to sound like the least onerous solution as I don't want to wrestle with the throttle quadrant in the upper left console again if I can help it.

--
Joe
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  #6  
Old 12-12-2012, 10:43 PM
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jthocker jthocker is offline
 
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Location: Cincinnati, Ohio
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Default

Quote:
Originally Posted by Joe View Post
Well, now I am confused. I'm amazed that yours works, Eddie. In my case, putting the throttle arm back in its original position on the FI servo is not an option: the geometry was totally wrong. The only adjustments on the cable are for position; there is no adjustment for throw. My FI servo body throttle requires 2.2 inches for full travel and the cable only provides 1.9.

Eddie, is it possible that your idle set screw (clearly visible in my second image) is adjusted differently than mine? I'm assuming Lycoming set it when they ran the engine but that may not be a good assumption.

Thanks for weighing in, Ron and Jon. Drilling another hole in the FI throttle arm is beginning to sound like the least onerous solution as I don't want to wrestle with the throttle quadrant in the upper left console again if I can help it.

--
Joe
In the past, I have found that if you have the green cable stop nutted as far forward as possible at the throttle quadrant ( meaning, the lock washer is on the fwd, side of the bracket, and the aft locking nut just catches some threads on the cable) you somehow gain extra travel. I don't know why this is but it has helped on carbed engines. If that doesn't help then drill that hole. Better yet, just drill that hole and move on!
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  #7  
Old 12-13-2012, 02:12 AM
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cdmiller cdmiller is offline
 
Join Date: Jan 2005
Location: Battle Ground, Washington
Posts: 138
Default Drill new hole in servo arm.

What Bruce Eicher said.

I had the same problem with the throttle linkage on my IO-360 M1. I drilled a new hole in the servo arm and it has worked perfectly for over 1200 hours.

Dan Miller
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  #8  
Old 12-13-2012, 02:34 AM
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Andy Hill Andy Hill is offline
 
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Default

Common problem... technically ideal solution is new Throttle Arm.

Precision were helpful and exchanged our arm for one 3/8" shorter - the price for a new one is a lot
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  #9  
Old 12-13-2012, 08:12 AM
Joe Joe is offline
 
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Location: Independence, OR
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Thanks, guys. I didn't realize this was a common problem but the solution is becoming crystal clear to me. Think I'll start by giving Precision a call but I have a drill press and am not afraid to use it :-)

Hopefully this thread will save some future unsuspecting builders some wasted time.

--
Joe
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  #10  
Old 12-13-2012, 09:28 AM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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Location: St. Paul, MN.
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Default

Had the same problem (first reported in this massive thread last summer). Contact Precision. They have two sizes of throttle arm and they'll swap out for the smaller throw at no charge.

Fixed the problem lickity split. I didn't drill anything.
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Last edited by LettersFromFlyoverCountry : 12-13-2012 at 09:31 AM.
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