I spent a whole lot of yesterday doing various things, which is the surest way to feel like I got nothing done. I had two goals: Fix the idle stumble and run down that AP engage joystick wire issue.
The first part was almost easy. I set the mag timing to 25 degrees per the engine data plate. I’m getting to be an old hand at setting mag timing. I got them both firing in sync, then made the idle richer by a couple of flats of the adjustment linkage, per the AFP manual. Sure enough, that cured the off-idle stumble and my CHT’s and EGTs dropped noticeably. But there was still a rough idle, so more adjustment needed to happen.
The manual says that adjusting the idle is done with the engine running. The problem with that is twofold: One, working near a spinning prop scares the crap out of me. I haven’t had the training to do so safely. Two, because of the orientation of the throttle body, the idle linkage is on top, between the throttle body and the engine case, and the only way to get at it is by reaching past hot exhaust pipes. Even if I did have the stones to crawl under there with the prop spinning, I can just see burning my forearm on the #1 pipe and yanking it back into the arc of the prop. No thanks. I did my idle adjustments with the engine off.
With Mike as the casual observer, it appeared that my idle was too rich, because there was a bit of smoke coming from the pipes when I was idling and the idle was definitely a bit rough. This is caused by multiple symptoms, but a too-rich mixture is the first and most obvious culprit.
The manual also says that the best way to adjust the idle is to leave one of the jam nuts “just snug” and turn the block one flat at a time. Well, yours truly interpreted “just snug” as “don’t touch” and after a couple of turns of the block, the left-hand rod end bearing snapped off at the jam nut.
So now I have to find/buy a LH thread #3 rod end bearing and I can get back to business.
As for the other stuff, I did chase down the AP engage wire. Turns out I have to figure out a way to do some kind of voltage differential and use the MGL script editor in order to remote-control the EFIS to engage the autopilot. A simple “Hey, I’m Grounded” won’t work. This will take a minute to work out the logic, but I’ll email Matt at MGL and see what he says.
Also, Owen and Ron got the racing scales, so I can do weight and balance. This gets done first thing today, because I need to return the scales ASAP. It’s I’m just hoping the W/B comes in as expected.
I also fiddled about with the wheel pants, but that’s not high on the priority list right now.