Vans Throttle Quadrant Control Throws

flickroll · #1 05-04-2009, 02:46 PM

I replaced the old style, long lever, Van's throttle quadrant with the new low profile style (throttle, prop, mixture). Although I bought it from Spruce, I believe it to be the same as the one Van's sells. First, the pre-drilled holes in the control arms are a little oversized. The clevis pins are slightly loose in the holes. Is anyone oversizing these holes with a drill and then using a bushing to tighten it up? I guess I could offset and redrill the holes but would rather not do that. The holes in the old style levers were slightly smaller and the clevis pins fit tight.

Second, with the mixture control lever, I am not getting full travel on the carb mixture arm. There is a space of about 1/16" between the carb control arm and the carb idle cut off stop when the mixture lever is full aft, and about 1/16" between the carb control arm and the carb full rich stop when the mixture lever is full forward. Looks like I need to drill a new hole farther out on the arm for a little more travel. Is this a typical problem with this throttle quadrant?

Thanks

drill_and_buck · #2 05-04-2009, 04:41 PM

Hi Jim:

I had a similar problem with the deluxe quadrant I purchased from Vans. I couldn't get the full travel on the mixture control lever. I ended up drilling another hole further out on the arm.

Don't make the mistake I did. I thought I would offset the hole aft of center to improve the aft travel. Moving the hole aft of center severely limits the travel of the clevis bolt and thus limits the throw of the lever. I ended up making a new lever.

Mike Draper
N468RV
RV-8 TMX0360, CS
Working on the canopy fairings....

flickroll · #3 05-04-2009, 06:26 PM

Actually, after I studied the linkage more, I now think the problem is the cable has too little travel, in my case only 2". The mixture lever is not hitting the stops so moving the cable farther out on the lever would make no difference. Van's now sells a mixture cable with 2 1/4" of travel which should be enough to give me full travel of the mixture arm at the carb.

cyrilmclavin · #4 05-04-2009, 07:18 PM

Guys its not the cable re drill lobe on the mixture control arm on the throttle body closer to the fulcrum did it om my 8a gives more travel on the lobe arm from the cable

cyril mc lavin

flickroll · #5 05-04-2009, 07:57 PM

Thought about redrilling the arm but there isn't much 'meat' closer to the pivot point. The arm tapers in where I would need to drill and would be worried about a fracture failure.