Grey Beard, the design of the mounts gives you a hard mount to the firewall, the two aluminum centers and the screw. The mount floats, but is trapped on the aluminum centers. I think the big difference is that the four stroke mounts are quite a bit longer than the 2 storke ones. That and the fact that the carb will interfre with one of the screw heads requires the engine mass to be an inch or inch and a half out front of a 2 stroke. It gives a little extra leverage, along with the low pitch prop and the torque from the four stroke.

I kind of agree that the rubber isn't tightended down, but if you notice that in the photo of the long and short aluminum centers the one rubber bushing was damage from being trapped between the spools because they were to short. I don't think shortening the aluminum centers is the answer. Maybe a shim between the aluminum center hubs and the bushings would work OK. Although I think I'm Ok with what I have now. It's not giving the snap to the side I saw eariler but a gentle change at full throttle, and then only during the spool up to the final 500 rpm or so.

Back when I was into street rods, you could get standard rubber bushings or neoprene bushings for the suspension. The later were quit a bit stiffer than the stock bushings. I suspect I need some Neoprene bushings here. Not realy though, as this isn't a pattern plane where precession is mandatory. It's just a knock around fun fly.

At least I can get onto the next step of the tuning process now. It is still a little nose heavy but for now, I like that as when I had it balanced out correctly, it was a hand full. I've got about two ounces one the nose now and will trim it down over the next week or so until I get more comfortable with it. Not having it go nuts on power on is a big plus.

Don