Rick Junkin

Thanks to all for the analysis and recommendations. I wanted to have an idea of what to look for when I went out to the airplane this morning and your inputs got me going in the right direction We identified two smoking guns. The first one was easy and obvious, and most surely will eliminate the surging. The fuel injector reference line fitting had come loose behind the rear baffle plate. Ambient pressure was going to the fuel servo, rather than pressures from the injection system, so it makes sense that I was seeing normal operation on the ground (~445'MSL here in St Louis) but having a problem at altitude once I started to lean at 30/2200. I had my annual about 20 hours ago, so that was probably enough time for the fitting to work its way off from an under-torqued condition. Something to add to my post-annual inspection checklist. The second one was the max RPM limit set screw on the prop governor (You were right, Lance). We discovered that the bushing the set screw goes through is stripped out, allowing the screw to migrate enough that the lock nut was starting to loosen up. It was only a change of 15RPM at full throttle climb out, but it was a change. This one would have been easy to miss because the screw was still safety-wired, and the max RPM was consistently hitting 2575. Right up until it wasn't. Prop control had continuously been positive, including being able to pull the RPM down on takeoff and work the the min/max range on the ground. We squared that away and I'm ready to go. I'm starting the New Year off with an early morning flight tomorrow to confirm today's fixes, collect the GAMI check data with the massives installed (EDM 700 download for temps, time stamped GoPro video of the panel for correlated FF/MP/RPM), and then I'll R&R the plugs with the Tempest fine wires, rinse, and repeat. I'll share the comparative data with anyone who might be interested. Thanks again for the point-outs on what to look for. Cheers, and Happy New Year! Rick

The airplane is an 89 TLS/Bravo, roughly 700 SMOH, 120 STOH with flow balanced cylinders from Lycon. No GAMIs with a spread of 1.2gph with 1, 2, 3, and 4 less than .5gph apart and bracketed by 5 and 6, high and low respectively. Massive plugs, with Tempest fine wires ready to go in. The intent of the last two flights was to baseline the parameters with the massives for direct quantified comparison with the fine wires. As to the prop governor, I'm headed out to the airplane this morning to have a look with my mechanic. It performed fine during the ground runs I did yesterday, but I did correct a 15RPM overspeed at full power on initial climb out immediately after takeoff, so we'll be looking to see if anything has come loose there. Thanks for the point outs! Cheers, Rick

Greetings all, I'm looking for information about engine surging at cruise power while leaning to cruise fuel flow, and resolutions to this issue that others may have discovered. I promised my wife I'd start with this - "Riddle me THIS, Batman..." I've encountered this on my last two flight attempts, after having convinced myself that I induced the anomaly on the first sortie with too rapid throttle/mixture adjustments. Flight conditions for the first sortie were 15,500 MSL at the top of the climb out, 34/2400 and 24.5gph (leaned slightly) set on the climb. After leveling off and reaching cruise speed, I set 30/2200 and began leaning fairly quickly to get to about 16gph, but the engine began surging well before then. It caught me by surprise, so I didn't catch all of the parameters during the fluctuations as I enriched the mixture to stop the surging. I tried leaning again with the same results, this time MP looked to be cycling between 30"and about 20", and I'm guessing that RPM was between 2200 and about 1000, based on sound as I didn't see the numbers. Unfortunately I don't have the instrumentation on board to capture the exact numbers. The surging stopped when I went full rich on the mixture and I left it there for an uneventful RTB. I did a run up post flight, and everything was normal. I convinced myself that I had induced this anomaly due to leaning in the climb (first time I had tried that technique) and percolated the fuel with higher than normal temps (1550TIT, CHTs 370-390), leading to a surge condition. On the second sortie (today), I was very deliberate in my adjustments and encountered the same anomaly. Today's flight conditions were 6,500 MSL at 30"/2200RPM, leaning from a cruise climb fuel flow of 25-26gph (full rich) at 34"/2400RPM. Leveled at 6,500MSL with 30/2200 set, I was leaning at a rate of about one full twist of the mixture control every 5 seconds. Leaning through 18.3gph the engine began to surge. I started enriching the mixture at the bottom of the second surge cycle and the surging stopped, so I then went full rich and I left it there for an uneventful RTB. Again, I did a normal run up check on the ground and everything was normal. I then did a high power run up to replicate the inflight engine parameters of 30"/2200, and leaned all the way through RPM decay with no surging. The peak TIT/CHT during the ground run was 1610/376. I also ran my prop through a complete min/max cycle at 2000RPM to hopefully rule out a prop governor issue, with no anomalies noted. Up to this point I have set cruise power and leaned to find peak TIT usually between 15gph and 14gph, and enriched 100DF. I've never had any surging. With the CND ground run results, I'm at a loss for what to look at. Could it be that one of the controllers is having issues? Or perhaps the mixture controller? It only happens inflight... Thanks for any insight you may have, I'm meeting a Mooney expert mechanic at the airplane tomorrow morning to take a look and will report back with our findings. Cheers, Rick

I just ordered a spare battery or my Sidewinder from this site for $65. I'll report back with my experience with it once I get to give it a try, but offering the info now for those looking for suggestions for stocking stuffers that didn't materialize this year. http://bigtimebattery.com/store/milwaukee_M28_replacement_battery.html Cheers, Rick

6 months, 57.9 flight hours, ~7,000 NM cross country and a bit of "flying around for fun". Looking forward to the next 25 years.

I just ordered a spare battery or my Sidewinder from this site for $65. I'll report back with my experience with it once I get to give it a try, but offering the info now for those looking for suggestions for stocking stuffers. http://bigtimebattery.com/store/milwaukee_M28_replacement_battery.html Cheers, Rick

Thanks Gents, I appreciate the immediate help! Cheers, Rick

Greetings all, and thanks for the wealth of knowledge you share. Which Tempest fine wire plug are you using? URHB36S and URHB32S are called out on the applicability chart, and I'm ready to order a set. Best regards, Rick