Ed_Wischmeyer
Well Known Member
So this morning, a friend and I saddled up the RV-9A for a few laps around the pattern as a combination of a persistent cold and bad weather had kept me grounded for too long. The temperature was 81 degrees in Savannah, so I almost didn't push the throttle in before start to use the accelerator pump, but since the plane hadn't flown in weeks, I decided to.
But the throttle wouldn't go in. The first third of the travel was okay, but the throttle wouldn't go in any farther with any reasonable force. Expletives deleted.
We pulled the cowling and disconnected the throttle cable from the carburetor. Throttle cable was fine, no appreciable friction. But the throttle arm on the carburetor...
A phone call to my good buddy and local IA suggested hitting the accelerator pump linkage and also the throttle shaft with LPS2. Did that, and instant relief.
Couple of things could have been going on. The accelerator pump apparently has a leather gasket that can stick. Also, sometimes carburetors at about 200 hours sometimes get funny wear on some of the plain bearings and tend to hang, but loosen up with more hours. Sort of like teenage rebellion...
But there's a lesson here, one that I'm not sure I've ever read about or heard about. Sure, I check all the flight controls for full and correct motion, and check that the brakes are firm before engine start, but I don't necessarily check all of the engine controls throughout their full range of motion. I almost didn't find this problem till I would have been out on the runway and suddenly discovered I couldn't get full throttle. And I don't necessarily pull the prop control absolutely all the way back when I check the constant speed prop on the RV-8.
Anyway, the flight went fine, even though it wasn't up to my standards. But on one landing in a crosswind, I heard and did not feel the upwind wheel start to rotate. But the patterns still weren't up to snuff. More practice to come.
But the throttle wouldn't go in. The first third of the travel was okay, but the throttle wouldn't go in any farther with any reasonable force. Expletives deleted.
We pulled the cowling and disconnected the throttle cable from the carburetor. Throttle cable was fine, no appreciable friction. But the throttle arm on the carburetor...
A phone call to my good buddy and local IA suggested hitting the accelerator pump linkage and also the throttle shaft with LPS2. Did that, and instant relief.
Couple of things could have been going on. The accelerator pump apparently has a leather gasket that can stick. Also, sometimes carburetors at about 200 hours sometimes get funny wear on some of the plain bearings and tend to hang, but loosen up with more hours. Sort of like teenage rebellion...
But there's a lesson here, one that I'm not sure I've ever read about or heard about. Sure, I check all the flight controls for full and correct motion, and check that the brakes are firm before engine start, but I don't necessarily check all of the engine controls throughout their full range of motion. I almost didn't find this problem till I would have been out on the runway and suddenly discovered I couldn't get full throttle. And I don't necessarily pull the prop control absolutely all the way back when I check the constant speed prop on the RV-8.
Anyway, the flight went fine, even though it wasn't up to my standards. But on one landing in a crosswind, I heard and did not feel the upwind wheel start to rotate. But the patterns still weren't up to snuff. More practice to come.
