I've fallen back to my number 3 airplane after engine problems in the number 2 plane. And have now have yet another engine issue. Just not my year, I guess. The plane is powered with a Saito 56. This setup ran pretty well previously, but has sat in the box (in a Ziploc bag, engine well oiled) for probably a year. I cleaned it up and put it in the plane along with a clunk tank of the same vent design used previous, though not the same tank. This is a new unit. All this worked fine previously.
So, I put 4.375oz in the fuel tank (previous amount needed to fly a pattern), prime the engine and flip. What I got was what you get when you burp a pipe plane. A quick wow! Start and stop like it starved. I keep repeating this process, all the while opening the needle. Started at about where I ran it before; around 3 turns out. At about 6 turns out, it finally starts and stays started...for about 20 seconds. I diconnected the battery and picked the plane up. Seemed to be running OK, but as soon as I tip the nose up it quits. Hmmm.
So I continue to mess with it. Got it started again several times and tried various positions. Same thing. The last time I started it and just held the plane level. It ran for about 45 seconds, pretty steady, then sagged a little and quit.
If feels like a starvation problem. Perhaps just a bad NVA? The engine had been stored without the NVA in place. I put an ST unit in (this is what was in before). It could be an air leak or just a bad NVA, I suppose. Any ideas on this?
I also thought it could just be bad fuel, so I cracked open a brand new gallon and tried that, Same thing, so I'm thinking this is a fuel delivery problem.
Oh, probably should say the venturi setup is my own design. Worked fine previously. a .310 venturi with ST NVA through the middle. OS 4 stroke plug. First fuel was some Powermaster 20/20 that I used previously in this engine (not year old fuel, just the same type). The new fuel was Wildcat 10/23.
Thanks for any input.