Think I have ruled out the regulator, tested and working fine, in fact my tank pressure holds for at least 30 minutes between flights, hisses every time.
The regulator is a bit like a glorified one way valve, there is fairly high pressure fuel coming in, that is released through the regulator by a vacuum on the carb side. Heres a tip to test:
1. I found a plastic pen with a cone shaped bottom part that will go through the regulator ring but wedge some way down.
2. Saw off such that 2 or 3 mm goes inside to form a seal.
3. Wedge it in and seal the other side with your finger.
4, Suck through the pen tube, it should be dead easy, air should flow through the regulator.
5. Blow and it should be impossible.
6. Connect a clean piece of fuel tube tube to the fuel nipple and it should be impossible to blow through.
Mine does all that fine so as I see it, a vacuum is amplified by the diaphram and opens a valve, high pressure fuel flows and is then metered by the needle valve. I may be wrong but I dont think the regulator plays a large part in fuel metering, I accept that way out UNDEMANDED pressure would cause havoc.
My initial starting problems were down to crazy rich settings and a lot of oil in the engine, that hasn't happened since I set the needles to 1 turn main and half on Mid, in fact Sullivan started reliably every time on a 3S battery.
Had another thought, downloaded the manual for the OS105 HZ, non regulated the needle valve holders are different, part no for regulated is: 29088940 and for the Non regulated 29085940, so could those little chaps at OS be putting a wrong part on there? It would probably be difficult to tell the difference!
