I finally got my OS70 mounted on my Aresti with Sig mounts. (Thanks Stomper.) Here's my concern. The top of the carb intake is approx. 3/4" below the fuel tank centerline. Can I expect to have siphoning problems?

Hmmm, you WOULD think so, huh? Try it and see. I'm assuming you have checked to see if you could lower the tank? If not, check it out. It might be possible.

Thanks Aeronaut,

I was hoping to install the fuel tank so it's cap would protrude through the hole in the firewall as per plan. I suppose I could install the tank lower in the fuse and close off the hole a bit. I was just curious if anyone with a similar setup had problems with this, and what their solutions were.

I remember on another thread here, somewhere, someone mentions that a fuel valve would prevent siphoning when the probe was inserted. The prob could be left in after fueling, and removed just before starting. Might be worth a try, if siphoning becomes a problem.

I ran my plane with an inverted engine and never had any real problem with siphoning. My tank was about no less than 0.5" above the carb. I did not use a fueling valve but re-fueled using the carb fuel line. Its a bit more tedious but no siphoning. I do not prime the engine prior to starting and it starts fine, hand started mind you. I find inverted engines have starting problems as the fuel DOES NOT feed into the combustion chamber properly.

I don't think you will have a problem if you are running a 4 stroke engine, it's the 2 strokes you have to worry about.

Mine runs fine, don't sweat it.

Thanks guys. I guess I'll see what happens once I finally get things put together. It's my first inverted installation.

I just noticed I never reported back on my OS 70/Aresti arrangement. The engine worked perfectly. I did need some help adjusting the low end. But ultimately it ran beautifully. I had a lot of fun with the Aresti for most of last summer. But around mid August I dumb-thumbed it into a soybean field and pretty much destroyed the plane. I've since cleaned up the OS70 and installed it inverted on a Venus 40. The engine runs nicely, but I had trouble adjusting the low end again. I'll try again this weekend. This setup may be dicier, since I don't think I have the tank centerline and carb near as close as I did with the Aresti.