Idle – WOT – ICO – Rich

Today I started where I left off yesterday, on the throttle issue. I started by verifying our trig from yesterday for the slave tube between the front and rear throttles. While I was doing that, I realized that I have two problems I am working and I had better work them in the right order.

The fact that I couldn’t get the front throttle to rig exactly how I wanted it was most important. The problem there was that I could get the throttle to positively make contact on the idle stop, or the wide open throttle (WOT) stop. But not both. If I pushed on the FI servo arms, it made contact, but the lash in the cable was enough to allow it to back off. There was about a .050″ gap on either end depending on rigging. While it is acceptable to positively hit idle, and have a small gap at WOT, I wanted positive contact on both stops.

The only way for me to correct this was to increase the lever arm from the pivot to the attach point for the cable. With all of these things in play, I ended up making a new throttle lever. The plan was to make a new throttle lever blank much longer than it needed to be (Thanks James) and start by drilling holes. The longer lever would give me multiple shots to get it right without having to start from scratch. To start with, I moved the pivot hole up the lever about 1/2 diameter or ..625 inches. I reinstalled and tested. It wasn’t enough.

So I tried a little bit further. It was too much. Turns out that right in the middle of attempt 1 and attempt 2 was the sweet spot. Positive contact on both idle and WOT. It still had about 1/16″+ of over travel on both ends of the lever. Perfect. But, there wasn’t enough edge distance anymore to make it an airworthy part. But it was a good template. So I continued.

Next I drilled a series of holes in the front throttle to test for the slave tube between the front and rear throttles. When I reassembled, I was able to determine which one worked. Armed with a “swiss cheese” template. I now could make yet another throttle arm. It is kind of a shotgun method… just need to keep track of which holes worked.


After transferring this to a new piece of metal, I checked again. Everything still worked, So I went ahead and attached my handles and the saga of the throttle lever is conquered. Incidentally, the mixture has been flawless all along. ICO and Rich stops are positively contacted without need for further adjustment. I didn’t get a photo of it fully assembled, but here it is before I added the handle.


By this time, Eric had come by to do some work on wiring. We were going to work on the dimmers for the interior LED lighting, but true to form, my organization (lack there of) reared its ugly head. We couldn’t find the connectors we needed. So we switched gears to engine sensors. Eric was a machine. He was able to get ALL of the engine sensors wired. That is all of the EGT, all of the CHT, the fuel flow, and oil temperature transducers wired. In addition he has gotten a start on the Tachometer pickup from the P-Mag. The routings have been set, but in these photos we have not secured the bundles. I am anticipating one more time of removing the engine from the airplane, and we will more than likely end up having to disconnect the connectors. So no need to secure them right now. The bundles look nice when they are secured, but you will have to wait to see the beauty of this until a bit later.




While he was working on that, I was able to do some wiring too. Or at least wire routing. I started on the alternator wiring. The alternator comes with a pre-wired connector for the field wire. So I routed that up to the VPX. The wire was a bit short of what it needed to be, but we needed to transition to the VPX style connector anyway. So Eric got the soldiering iron out and spliced the wires. Field wire is installed. I also planned on running the big wire to carry the alternator output, but I need to order the right size ring terminals.

By this time it was the end of the night so we had to do one more thing. Turn the EFIS on and see the indications. All of the temperature probes were showing indications. The EGT and CHTs were between 60 and 63. The oil temperature probe was showing 70, which was very close to ambient temperature. I would guess the variance is due to the sensing ranges of the probes. The EGT and CHTs operate in the 1100-1400 and 330-450 range respectively. They may not be accurate at such low temperatures.


Throughout the day, I was thinking about tasks remaining before engine start. Specifically some of the wiring tasks, so I made a list. I am hoping this will help me get some organization in finding parts I have and ordering things I need. Today we got to cross three of them off and get started on a few more. Plenty more to do, but the lists are shrinking to a more manageable size.


There are plenty of engine tasks remaining, I just didn’t start writing the down yet. Hopefully scheduling leaves me alone tomorrow and we can knock off a few more things.

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