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Throttle linkage question

Desert Rat

Well Known Member
Hey Guys- The throttle cable bracket geometry on the IO390 results in the cable end being offset inboard from the lever on the AvStar fuel controller.

Vans drawing OP-22 has you make a 3/8" long spacer out of aluminum tube to be used in conjunction with an AN3-14 bolt to account for the offset. This seems like sort of an unnecessary band aid if somebody just makes a throttle arm with less of a bend in it.

Has anybody just gotten a lever arm with less offset? If so, did you just order it from AvStar?

Is there any particular reason that requires the Vans setup or did they just go on the cheap to fix this particular mis-match?

edit- on a related note, why the heck are my pictures suddenly showing up sideways? :)
 

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90 views and nobody has an opinion on this? That must be some kind of internet record.

I should have worded this with a view toward more controversy, i.e. "Hitler loved the standard throttle linkage spacer so it's good enough for me."

Or perhaps the opposing viewpoint, "If you replace the standard linkage you're for sure 100% gonna die."
 
My experience was similar, but on a vertical intake Superior IO-360-B1AC2/Silver Hawk EX Fuel Injection Kit. I had an issue with the bend and geometry on the linkage. Precision Airmotive swapped out the 2-inch z-arm for a 1 5/8 inch z-arm that had a different bend/geometry.

I would agree with you. The spacer looks less than optimal. If you could swap it out for one w/out the bend with the right geometry, that would be ideal.
 
I mistakenly thought I needed a straight mixture arm for my Precision Airmotive servo and found lots of arms with part numbers, but no descriptions. McFarlan has them. The opportunity to prolong the build by another day and a half for no reason was irresistible so I made my own from 416 stainless. No wonder this is taking so long... I don't think it's the same throw as a throttle arm but I can measure next time I'm in the shop if you're interested. Pictures of it being made are under "Engine" -> "Fuel Injector Arm" in my EAA Builder's Log; link in my signature.
 

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See my post under my tag name. I just got done working this area. Here are my pictures.

I got my straight arm from the manufacture of the throttle body; cant remember if it was Avstar or not.
 

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Thanks for the input guys. Nicky, are you saying you don’t need that one in your picture?
I’m out of town this weekend but when I get back I’ll measure the length of what’s on there now.
 
Happy to send it to you so you can see if it works. If it does, send me $75.

I will measure mine and post the dimensions.
 
Here are some pictures. I don't think this will work well. I think the 3/16 or so difference in length will make your throttle twitchy.
 

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