I Just purchased a Satio 1.80 for my Great Planes Giles. Every time I run it the intake comes loose from the head. I have tried thread lock but it still comes loose. Any suggestions.

If it's still under warranty talk to Horizon Hobbies service department. Maybe you can return it for repair. Or ask for some new O-rings. If not try some silicone sealent where it slides into the O-ring. Make sure the surfaces are oil free and don't let any get inside the intake tube.
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The problem is it does not use o-rings it is threaded with a compression fitting. The bolt comes loose then causing it to leak.

Thanks

Cook, there is an easy fix for that, get some teflon plumbers tape and put a couple of layers around the compression nut threads in a clockwise direction, then tighten it up rather firmly, don't be shy about it and it will never get loose again. Do the same on both ends of the exhaust stub.

Thanks will give that a try.

Cookie:

I find that if I will warm the engine, and tighten both the intake and exhaust while it's all hot, I don't have the problem.

Bill.

I ran it again to night but I could not keep it running. It seems like on the exhaust stroke the fuel it forced back into the tank and the carb is starved for fuel. I could not even adjust the needle valve. Will keep working with it.

Thanks

Have you had this engine apart for any reason? Just asking!
Have you checked the valve clearances? If the exhaust stroke is forcing the fuel back into the tank the intake vlave isn't closing soon enough or the exhaust is openiing to soon. Maybe!
As far as keeping the intake maniflod tight go with the teflon tape as hobbsy suggested or some high temp silicone will hold both the intake and exhaust nuts. I've used that on some of my other four strokes with success.
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I checked the valve clearances last night and they were good if anything just a little on the loose side. I ran the engine on Sunday and it ran well just could not keep the intake tight and I had a flex muffler on and it broke so i made modifications to the plane to accept the stock muffler and it just would not run. I would choke it by holding my finger over the exhaust port and then on the next flip the fuel line would not have any fuel in it. Thanks for all you help guys, this one has got me baffled.

The fuel flowing back into the tank between flips is an indication that one or both needles are way too rich, when set correctly it has enough drag that the fuel stays put between flips.

Cookie:

"...one or both needles are way too rich..." or the tank is way too low.

Bill.