Hey HarleyGal,
Glad to here you have her run in.

When you installed the Ofna Valve you effectively changed the tune of engine dramatically.

Without the valve the fuel system is what is called an open fuel system. In other words there and a clear path to the outside atmosphere via the pressure tube that goes from the Exhaust nipple to the tank(there is no mechanical obstruction/valve). So when the engine was running the fuel system relied exhaust pressure to pressurize the tank/fuel system. Well when the engine is at idle the tank has decent pressure, then when you stab the throttle the exhaust pressure rises rapidly so help feed the extra fuel to the carb. But when you let off the throttle the pressure in the tank drops suddenly so it wont flood the engine. Well, thats ok on a system with smaller fuel tanks but when you have tanks as large as the 220cc onthe Genesis series truck you have more space in the tank to pressurize so this effect does not work as fast and when the tank is half full it takes much longer to pressurize the half full tank and you suffer from the now infamous Half tank lean issue know to plague these open fuel systems on larger tanks.

You can find the thread here on RCU that discussed this problem in depth by searching for [link=http://www.rcuniverse.com/forum/m_4462148/anchors_4462148/mpage_1/key_half%252Ctank%252Cleaning%252Cissue/anchor/tm.htm#4462148]"Fuel tank/motor issues.... Again..."[/link]

Ok, now after long deliberation on this problem I realized the real problem was the lack of stable pressure in a tank this size. I then theorized in the thread that what is needed is a checkvalve of some sort to hold pressure in the tank longer after you let off the throttle. The search was on to find a valve that worked, and I literally tested a dozen or so valves!! In fact I almost gave when I ran acrossed the Ofna Primer/Filter, and I thought what the heck try one more time and ordered it. Well, it wasn't a total success at first. I could not get a good tune for the life of me. Until it hit me I am adding ALOT of pressure to the tank and I now need to control that pressure better by leaning out the needles Drastically, Starting with the high side first. So I started the engine and started turning the High Side Needle in until it started to run better and did not seem to load up(flood) as much. Then I went to the Low Side to control the idle mixture until it idled well and would accellerate quickly

The point is now that the valve is on you will need to lean high side Needle then the low side needles quite a bit. It will vary how much depending on your region! You will have to find that sweetspot yourself, but its there!! Just be patient and only turn the needles 1 hr increments. Dont be surprised if you end up turning the high side needle more than 1 complete revolution. I live in the American Southwest(Sonoran Desert) very dry and very hot in the sumer(over 105*f for more that 30 days in a row!!) So I had turned mine 2-2.5 complete revolutions to find the sweetspot.

Now I know that was more than you asked for, but you got it!!

I hope it helps!!

Contact me as soon as you read this to let know if its clear enough for ya