As it turns out, there's no need, really, for any kind of preheat or glow start. Went flying tonight with the dieselized Norvel .074 and the LM heat sink headclamp. Things didn't go as smoothly as at the bench but the evening became quite cool, compared to the afternoon, which involved a blistering sun and temps in the 80s. So the settings were a little off. Just a little. As the last run was with the ether mix, that was tried first. After three prime bursts, the engine caught and kept running. Rough at first but after a bit it smoothed out and I tweaked the needle with the nose up and off I went. The compression screw was left alone.

Touching nothing, I fuelled up with the no ether mix and had a go at it. Six prime bursts and nothing. By this time the engine had warmed up a little so all it took was a tweak in on the compression screw, ( just a tweak) and she lit off. After a bit I backed off the screw to about where it was and we had a run. Solid, LOUD,,, but smooth. The idle got a little ratty. Well, a LOT ratty. Rumble, grumble, brrrr, puff and so on. But the idle, just under 5K, held. I sat for two, three minutes and it did its noisy thing steady and solid. OK, how's transition? At two clicks above idle, it smoothed out and the plane lurched forward so I just punched the throttle and off she went. And I proceeded to put in a normal flight. Well, except that the idle still had character. Lots of it, not like a grrr but more of a gurgle. I wish I could say it never quit but it did, once, on an attempted touch and go. A half dozen touch and goes later and it never did that again. Just all that noise and fuss. You can get a sense of what I mean on the video but trust me, the video is real kind about it. But as the video also illustrates, the throttle response IS instant with no hesitation. The engine did that in the air, in spades. So, as in post 83, we still have an idle that appears undercompressed, or is too rich, or both. As before, I have the airbleed all the way out with no effect. So, apologies to the medical profession, we have a symptom that needs to be looked after.

But now, here's something interesting. A cool engine needs advanced timing to get a start and once running, the timing needs to be backed off as the engine warms. We do that with the compression screw. However, there's another way to advance the timing. Load the combustion chamber with a rich fuel mixture. We do that, after all, when we drown a glow engine with raw prime to get it started. Remember the old days when you used a hand choke to start your car? Ever wonder why you did that, or how it worked? So I backed off the needle valve a full turn, gave it a shot of prime and she lit off, first try. Rough, real rough so I got on the needle right away and bit by bit, as the engine warmed and I dialled it in, I finally arrived at that just right setting for a strong run. No attention whatever, was paid to the compression screw. This mirrors my experience with this fuel on the bench, earlier in the day.

But it gets better. Again, with a cold start, as I applied the starter, I plugged the muffler with a spare finger and lo and behold a burst with no prime. Yes, the needle was backed off a full turn. A second try and she caught and faultered but this time I used the finger to adjust the amount of fuel delivered by muffler pressure, as required, and I milked the engine to life. After it caught and held, I got on the needle to bring it up to RPMs as before. Neat.

There's no question that the ether helped to smooth things out a fair bit. BUT, the engine started and ran and ran strongly at full bore. I have a philosophy that a machine was meant to earn its keep and I know that I'm *****g the needle and compression more than some would like to see. The sharp buzz at full bore is evident, especially in the air. Still, with the pedal to the metal, the engine keeps coming back after a flight, like a puppy, all smiling and goofy like. Well, maybe that's me projecting myself into the machine.

So there we have it. Norvel diesels run on an all kero fuel and this is with 50 weight, non detergent, aviation oil, hardware store kerosene and a quality cetane booster. If not for the Amsoil, maybe none of this would be happening. I owe THAT one, big time, to Kelly. Thanks again, man.

And there's still more to experiment with. Other brands or types of cetane booster. Hey, Amyl Nitrate. What if,,,, Or a magic blend of ignition improvers. Never mind the chemistry, poke and prod and just TRY it. You never know. Sure glad I did.