PT20J

When I was testing the Garmin Smart Glide, I noticed that I had to pull the prop back in my M20J or the rpm fell in the yellow arc at idle throttle and best glide speed.

No worries -- none of us knows everything and we are here to help each other.

Is the slop in the steering or the pivot? And how much slop is there? Slop in the steering can be checked by jacking the airplane and grabbing the nosewheel and twisting it from side to side and noting where the lost motion is in all the visible components. Slop in the pivot will be noted when moving the nosewheel front to back. Mooneys typically have some play in the steering that gets worse with wear. The wear points are the steering horn and the rod ends, not the truss. You can shim the horn until it gets bad enough that it needs to be rebushed. Rod ends are easily replaced. If your mechanic thinks the truss pivot is worn, then perhaps the LASAR bushing mod is a good option. However, you might first try checking the torque on the pivot bolt.

@Marc_B is correct. The advance (20 or 25 deg) is set by dip switches when you install it. So, you can set it for 25 and if you don't like it you can change it to 20. (You will have to remark the engine data plate if you change the timing and make the appropriate logbook entry). The only choices you get when ordering are whether you are replacing an impulse coupling mag or a non impulse coupling mag.

But the service bulletin says MIL-PRF-23827 mixed with 10% (by vol.) Molybdenum Disulfide. So, wouldn't you still have to mix in 5% moly with AS 33 to meet the spec called out in the AD?

Doesn’t the AD reference SB M20-190 which requires 10% moly by volume? I don’t believe there is such a commercial product available. LASAR used to mix it and sell it in small containers - perhaps they still do.

According to the M20J Service Manual, the proper lubricant for the hold open arm is MIL-L-3545 grease which is Aeroshell 5.

Let's see: GAMI has over ten years of research, development and testing. Some testing was witnessed by FAA personnel and the results were approved by the FAA resulting in an STC. Much of this is described on the G100UL.com website. The Youtuber was not vetted by anyone. His test was not observed by anyone. We don't know his motivations. Maybe he was paid by Swift. Maybe he dosed the 100LL with paint stripper. Probably not, but the point is that WE DO NOT KNOW. Yet some seem to give high regard to the Youtuber while denouncing every argument George puts forth to explain the G100UL testing and certification process as tainted by self interest. George has offered to share the contents of the certification file with anyone interested in visiting Ada to view it. That's pretty unusual. I know of no STC I can purchase that comes with certification and test data to support the FAA's decision to approve it. If anyone has a beef with the approval process for G100UL, I respectfully suggest that you should take it up with the FAA. I continue to support continued independent testing. But the results of the Youtuber need to be repeated and confirmed by others before they are taken seriously. Anyone remember cold fusion? It looked promising until it proved unrepeatable by peers.

George @George Braly, forgive me if I misunderstood the test. The G100UL.com website FAQ states in pertinent part, "Those three Beechcraft painted louvre panels were immersed in:" Upon review, I see that the text is somewhat ambiguous. I took "Beechcraft painted" to mean "painted by Beechcraft." From your response, I believe you intended it to mean "painted panels removed from a Beechcraft."

Lube the baggage hold open arm also!

I would think a dry film lube would be best on the starter. Evidently DuPont used to make Teflon lubricants, but as @A64Pilot said, its current products utilize boron nitride. A friend showed me a spray can of boron nitride he got years ago in Japan, so it’s been around a while (I don’t know who made it: all the writing was in Japanese). It sprays out as a white powder (so it’s a little messy) and is very slippery.

I agree. Something happened to the painted parts in the video. The test should be repeated by others with sample parts from various aircraft with different paint systems. The GAMI tests were all with Beechcraft panels. Beech is known for quality. Who knows about the paint systems used by Cessna, Piper, Mooney, etc.

The power for the gear down, gear unsafe, and floor gear position light comes from the Gear Warning circuit breaker and the lights are controlled by the gear up and gear down limit switches. This circuit also supplies power to the gear warning sonalert. With the plane on jacks and the gear up, closing the throttle should cause the sonalert to sound if the throttle switch is working/adjusted properly and this is a check that the gear warning circuit has power. If not, you’ll need to trace power through all the connections to find the issue. The throttle switch should only control the sonalert, so it’s curious that wiggling its wires affected the lights. Since the switch has been replaced and wiggling the wires no longer has an effect, I would ignore this for the moment and check that the gear warning circuit has power first.

Half a degree engine to mag timing shouldn’t have much effect on CHT. Internal mag timing (E-gap) primarily affects spark intensity. Lycoming SI 1437 describes two methods for setting timing. Method one won’t work on a M20J because the spinner backplate obscures the timing marks. Method two is what I use. The Lycoming tool is ungodly expensive, but many people just use a straight edge on the crankcase parting line. I use this tool which makes it easier and is reasonably priced. https://www.aircraftspruce.com/catalog/topages/pointers.php?clickkey=1596921

Only FAA determines airworthiness requirements, so if you have an STC, it’s approved by the FAA. Liability is determined by the courts. Lycoming’s statement may or may not help it in a court case.

On my ‘78 J I solved the problem by slightly bending the piece indicated to increase friction on the cam. I may have had to remove the knob to do this. It was 30 years ago and I don’t remember.

@MikeOH we get your point: You want 100LL and G100UL in place simultaneously everywhere you buy fuel until 100LL ceases production and G100UL has been proven to cause no harm. That's not going to happen. There is no infrastructure to support it. And no business person is going to put in a second tank (or truck) at great cost for a situation that will only last a few years. This continued harping on this point is distracting from the very real concerns that have been raised and need to be addressed regarding o-rings, tank sealant, and paint. I understand that GAMI has done years of testing. Some testing may have included third parties; I don't know. The FAA reviewed it all and approved the STCs. But, that was only testing in a limited number of circumstances. The test matrix of all possible combinations in the field is immense. I spent my career in tech product development and I saw many instances where well tested products had unexpected problems when released to the field. Those of us that frequent this forum (or Beechtalk) need only recall Garmin's pains with the GFC 500. If I were GAMI, I would avoid trying to explain everything with "we tested that and found no problem" or "100LL should be worse" and aggressively investigate every report of issues while G100UL distribution is still small and manageable. It doesn't take many issues in this day of the internet to get a population down on a product. Some of those pilot/owners will have their elected representatives on their speed dial. Just my $.02.

But, George’s “replication” was reported to be using 94UL in a Continental IO-550. The UND issues occurred in Lycoming O-360s. https://www.aero-news.net/index.cfm?do=main.textpost&id=39119893-8D1D-43AE-9323-CA08523C6439

UND replaced its entire fleet with new Archers and Seminoles in 2016, so yes.

I believe Lycoming switched to hardened seats sometime in the ‘90s in preparation for future unleaded fuels. It was mentioned when I took the Lycoming factory class but I don’t have any documentation on it. If you want the details, you could call tech support and see if there is a service publication. Lycoming only puts the most commonly requested service literature on its website, so there may be something that you cannot find by searching the site.

Looks to me like an IO-360-A3B6 engine with the bracket for a -A3B6D engine. Probably why there was interference.

Very nice.

I suspect that the longevity is highly dependent on the quality of the original application. Personnel changes over the years, factory shutdowns and restarts, etc. might cause gaps in proficiency. The two women that did tank sealing that were interviewed in the Boots on the Ground video admitted that it was a challenging job and had a learning curve and that they weren’t very good at it when they started. Someone got the airplanes they learned on.

Yes

I believe the seats use a hitch pin Rather than a cotter pin.