Fox Twin She Lives!

[00:00:08]Hello and welcome to beautiful Picket, Wisconsin on this Monday, July 20th, 2026. It is opening day for EAA Air Venture 2026 and I was at the SE plane base earlier this morning. Today I am here to do a run for this Fox Twin cylinder engine of a customer of mine, customer of mine. So, in my last video that I shot in the garage, I was showing the setup and all that. And I just taken some more pictures here that I'll put on here prior to the run and show you this.

[00:00:45]And I was talking about how much compression this engine had and how my starter wouldn't start it, turn it over and everything. There were some suggestions and some really good ones because my thought was take a plug out and do one cylinder at a time, but there were some suggestions about just loosening both plugs slightly, get it running and then tightening them both up. That's a good suggestion.

[00:01:10]Not an ideal solution and for two reasons. I don't really want to have to be trying to do that because what if the engine dies and then it's like, oh crap.

[00:01:20]So anyway, I don't want to have to do that.

[00:01:24]And I also have these remote glow igniters on the plugs, which makes that impossible to do with that. So I'd have to start, you know, use two different starters or nice starters on there. So I came out here and I had one of the plugs loosened a little bit. And just for the heck of it, I put my electric starter on there and it turned this engine over easily.

[00:01:45]I had this battery on charge for a day and a half and maybe, just maybe, it wasn't really charged fully because then I tightened it back up to get full compression again and it still turned it over.

[00:02:01]So, let's just go with the fact that this thing was wanting to turn it over and that's how we're going to do it. So, I didn't mention the weather. It's 77°.

[00:02:11]The last week or so, there's been a lot of wildfire smoke from Canada into the state, and the air quality has been unhealthy to very unhealthy and and it just looks weird. The air quality is not super great right now. I don't think this engine's going to care.

[00:02:29]But it is breezy. It's very windy. So, I'm hoping a that you can hear me. And I'm hoping that my wind buffer on my microphone you allows you to hear me and this engine. So, what we've got here is a remote glow igniter supplied by Wayne, buddy of mine in Australia, who also gave me the big nickel metal hydride stick that I'm going to use to power this. I've got a Zinger 138 prop.

[00:03:02]The Fox manual said a 138 prop would be good. This is a 138. I just wanted to go with the wood prop to start with just because it was more period correct.

[00:03:13]I've got these carbs preliminarily set.

[00:03:16]Now, it's not going to be possible for me to adjust the low speed on this one while it's running. So, I don't know how this run is going to p pan out. I've got a little bit of fuel left in a tank over here and a little bit of fuel left in my uh vehicle if we run out of this and I'm still having fun. Otherwise, I have no issue with coming back later this week and running this engine again, too. So, we'll just have to wait and see how it goes. So, those are the parameters for today's run.

[00:03:46]Let's just I'll put up the pictures that I took of this setup and then we'll just start a run.

[00:04:35]Okay. I don't know how concerned I'm going to be with getting RPM readings.

[00:04:43]I think it's more important just to see if we can get this thing to run first.

[00:04:47]So, I'm going to go ahead and plug my battery pack in. I do not have the ground wire connected. So, I'm not energizing the plugs yet.

[00:04:58]Make sure that stays connected to this rubber band so that I'm not energized.

[00:05:06]Really would like this to go someplace else. Maybe there it'll sit. I don't know. We'll see. So, I've got the fuel lines hooked up. I've got the throttle lip full. So, here's the thing. I usually always prime by covering a barrel of a throttle.

[00:05:27]So, because there's two carbs on here, I'm going to have to see if I can do it with one hand and watch my fuel line here.

[00:05:53]Okay, I believe it got took fuel.

[00:06:00]I believe it took fuel.

[00:06:18]It's hard to feel if I'm actually getting fuel. I thought I saw fuel go up in there.

[00:06:29]Maybe I just do this.

[00:06:36]Now I know there's fuel in there. So, I'm going to start it. Attempt to start it at about 1/3 throttle. Now I need to find a ground point.

[00:06:47]Maybe I can ground it there. That would be nice and convenient.

[00:07:22]Heat. Heat.

[00:07:41]Heat.

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[00:10:33]Heat up here.

[00:11:07]Okay, I shut it down there. Um, yes, I was seeing it running. Both cylinders were running. This one was was uh shutting out initially, but I've got this high-speed needle pretty closed on this. What I want to do is I want to close this low speed just a little bit and see if that changes anything on this side.

[00:11:29]Um I this this setup is really nice because I can actually just plug it back into this back screw and re-energize both plugs. And that's how it was running.

[00:11:43]So, hey, guess what? It ran. It ran pretty darn good considering all things.

[00:11:51]Um, initially when I started it up, this this cylinder was running fine. This one was kept cutting out. It was stone cold.

[00:12:01]That's when I started leaning this high-speed needle and putting the glow igniter back on. But hey, I'm pretty happy with this so far. We've gone through quite a bit of fuel. So, I think what I want to do is let this cool for a few minutes, and then maybe I'll siphon fuel from that tank, put it in here.

[00:12:19]Now, the thing I didn't mention was that I've got two brand new Fox RC long plugs in here, and those are idle bar plugs.

[00:12:27]The ones that came in this engine were the same plugs, but they were very old, and they just didn't glow very good.

[00:12:34]This is about 5 to 7% nitro fuel. So, let me give this a break. And uh I see a peak reading here of 9,50.

[00:12:46]So, hey, not bad.

[00:12:51]Okay. I hope this isn't really a bad idea, but I wanted to swap propellers.

[00:12:55]So, I've got a master air screw 146 on here to make it a little bit larger.

[00:13:00]Um, but the crankshaft is so short that I couldn't fit the back plate of the spinner on. So, I'm actually running this spinner without a back plate. And that's the part that I hope isn't a bad idea. Never done that before. So, um, the other thing is I don't particularly care for my angle. And this angle works really well for upright engines, but it's not doing so well for this engine.

[00:13:26]It's showing it off. So, I think I'm going to fire it up here real quick.

[00:13:30]Perhaps maybe get a couple attack readings and then I'm going to shut it down if it runs well again. Shut it down and maybe angle my camera from this direction downward so you can kind of see the operation or see the full engine better because this side view just really isn't doing it for me.

[00:13:50]So, I don't know that I need to prime this. It looks like there might still be fuel in the line.

[00:13:57]So, let's just uh plug this in. Energize our plug.

[00:14:25]Heat.

[00:14:38]Heat.

[00:14:58]Okay, for whatever reason, this cylinder didn't really light this time. It lit and then it died out. And I don't really know why it would do that. Nothing has really changed.

[00:15:14]Let me open that back again and see what happens here.

[00:15:20]This cylinder seemed to be running fine.

[00:15:22]I maybe I probably should have been taking some uh tack readings with it, but it wasn't.

[00:15:49]Heat up here.

[00:16:15]Heat.

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[00:16:44]Heat. Heat.

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[00:17:33]Okay.

[00:17:36]I was running and I left the glow igniter on completely uh because it just seemed like that was the better way. I and in reality I forgot to disconnect it to see. But I think what I want to do now is do the rest of the run or runs that I do here with this at a different angle. Uh you saw a peak RPM reading of 10,180 with a 146.

[00:18:01]Um that's pretty respectable. So I'm just going to leave it and say, "Hey, we're good there. Let's just do some more. just run some more fuel through this thing and see if there's It seems like this cylinder when I leaned out that low speed needle after the first segment that this cylinder seemed a lot better. Um maybe I need to do the same thing here.

[00:18:25]I just put about three clicks on that.

[00:18:29]And like I said, I'm going to change camera angles now.

[00:18:33]Get some different shots of this and do some more run.

[00:19:12]Heat. Heat.

[00:19:33]Heat up here.

[00:19:58]Heat up here.

[00:20:35]Okay. So, there's a good run. What I want to do now Since things are going so well, I'm going to let this engine cool down once again. I'm going to go get the rest of the fuel in my tank or in the truck. Put it in this tank. And now what I want to do is I want to open these throttle stop screws a little bit and see if I can get a little bit lower idle because that last little adjustment here on this low speed needle on this side seemed to help this cylinder quite a bit. And I think they're both high speeds are set pretty well. So, and for the most part, if you see me doing this, it means the glow plug is not being externally ignited. If you see me connect it, then it is and it should be obvious. But the last time I did that, I didn't hear any difference.

[00:21:22]So, I was like, okay, I think we're we're pretty good now. So, I'm going to cool let it cool down, fill this tank up with the remaining f fuel I've got, and probably just open each of these maybe a half a turn. So, we can see if I can get about a 300 RPM or 3,000 RPM idle.

[00:21:43]Okay, so I filled up my tank again and I've opened each throttle stop screw half a turn. So, that should give me each. So, it should give me a little bit lower RPM.

[00:22:00]And let's see what happens. Now, now with the camera being here, it's makes it a little bit tougher for me to start this engine.

[00:22:08]Let me see where I'm at. I don't want to be at full throttle.

[00:22:34]Heat.

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[00:26:02]Okay, I wanted to stop it there. Looks like this low speed can be dialed in two more notches. Um, my ears are ringing.

[00:26:13]It was running really well there. Um, I think I recorded a low speed. My tac doesn't record hold the low speed, but I got down to like 3600 and it seemed like this cylinder dropped out a couple of times and that's when I'd hit it. You'd hear it pop back on.

[00:26:30]So, I'm going to let this thing cool again. I made those little adjustments to this carb.

[00:26:37]This one seems fine. Now, this didn't have the same peak reading this time. I think it only got up to like 98.40 this time as opposed to over 10,000.

[00:26:51]But, you know, I'm fine with that. It doesn't need to be massively peaked out anyway.

[00:26:57]So, I'm going to let it cool and we'll do one final little run here and then a wrap-up.

[00:27:04]Okay, probably the final run of this thing for the day and maybe forever.

[00:27:08]It's cooling off some. The wind is really helping out. I was really hoping that the sun would stay behind the clouds because I think it looked better in the shade, but oh well. Let's connect our glow and fire it up.

[00:27:49]Heat.

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[00:30:14]Heat. Heat.

[00:30:44]Okay, let's just run this fuel out here real quick.

[00:31:01]Okay, I think we're done.

[00:31:05]Holy crap. This was probably one of the most enjoyable engine runs I've done in a long, long time. This thing really, pardon me, but this engine really kicks ass. I really like it. Now, how it would work on an airplane, obviously, I can't say. I'm oil soaked. All I can say is on this stand, on this day, under these conditions, I think I my hearing is affected. I think this thing ran pretty darn well. So, the thing is, I had myself so psyched out about being able to get this thing running and tuned that I am incredibly surprised and happy right now because I really didn't think I' I really wasn't sure I'd be able to get it running, especially as well as it is running. So, I have no complaints.

[00:32:00]This thing is awesome. It's fun to run.

[00:32:03]It's even with the exhaust, it's loud. I can only imagine what it would have been like had I tried to run this without mufflers.

[00:32:12]So, I hope in these last few shots looking down like this that you were able to see the amount of oil that's coming out of it. Both cylinders. Now, I think this exhaust diverter is kind of angled up more, but this one's really wet over here. This is really wet over here, too.

[00:32:33]So there was definitely adequate lubrication going through this engine.

[00:32:38]Man, this thing is just fun. I mean, that is fun. I It's all I can say. It's an en This was really, really enjoyable.

[00:32:50]And I hope everybody learned something.

[00:32:52]I know I learned a lot about this engine, about myself, about running a spinner without a back plate, which seemed to be okay. I really like this 146 prop on here. Now, when I ran the 138, I didn't have it tuned properly. It wasn't even It was just running, but it wasn't tuned. So, I don't know.

[00:33:12]Who knows? I've got some fuel left here.

[00:33:14]Maybe I'll throw the 138 prop on there again with it like this and shoot another quick segment so that we can see with it tuned exactly as it is right now. See what it does with that 138 prop.

[00:33:28]Why don't we just do that? But I'm going to go ahead and let this thing cool long enough for me to swap props. We'll put that on again.

[00:33:37]And the bonus segment of this video will be another short run with the 138 prop, probably from the side view so that you can see the RPM readings instead of me trying to set it up like this again. So, let's do it.

[00:33:53]Okay, bonus footage. 138 prop may not be much different than a 146. I think they're approximately equivalent, but there's only one way to know for sure, and that's to try it. So, let's do it.

[00:34:30]>> [snorts] >> Heat. Heat.

[00:34:57]Heat.

[00:35:02]Heat.

[00:35:18]Okay, that'll be it.