Sync Master (Bill Stone)

Bill has volunteered to be our first out of house tester for the Sync Master throttle system for the Rotax 912 engine. This blog will be updated with information every time that he comes in to the shop. We installed the Sync Master throttle system on his Just Air Super Stol which has a Rotax 912ULS 100hp engine installed.



You can see the slack in the cable at the carburetor after 49 hrs of operation. Originally there was only a small amount of slack. It is possible this was simply caused by the new cables stretching a little. He still had a full stroke from idle to full throttle so this slack was of no significance to the Sync Master’s operation.

As you can see here the idle was off by about three bars on the SynchroMate Carburetor balance tool. We would expect this because the engine was new at install. It is common for the carburetors of the 912 to slowly become out of synchronization  over time.

This photo was taken with the engine at 3000RPM. The photo is a little blurry but you can see that we are out of synchronization by almost five and a half bars. This is most likely to the cables stretching.

Here we have made adjustments to the idle screws to get the on idle sync within half a bar.

Within a few minutes we were able to get the carburetors synchronized by just turning the jack screw of the Sync Master. With Bill’s install the Sync Master is in the cockpit of the aircraft. It is mounted under the right side of the instrument cluster. This allows us to easily make adjustments to the throttle cables while the aircraft is running. With the SynchroMate installed on the engine this makes for easy synchronization of the carburetors. We adjust the jack screw till we are centered on the SynchroMate and then do a full power run up. This allows us to come back to the same rpm and verify that we are still synced. It took us about three run ups and we were dead center.
Just a note to those of you who have not done a carburetor synchronization. The carburetors will not be synced throughout the throttle stroke. It will usually go out of sync and then back toward the center as you accelerate.

There will be further updates on Bill’s installation as he comes in for inspections. I will also be adding a post about the first installation that was on our Rans S6 Coyote.

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