I understand from what I have been reading that these devices regulate or pump fuel from the tank. Is this right? How exactly are they doing this and how would I use one? Also, where can I find these devices and which one would be better for a 3D application (O.S 1.20AX)? Granted, I can fly the planes, but still learning this side of things...
Thanks,
Chris B

www.billsroom.com/pcfs for the Cline, the Cline and IronBay regulators are demand regulators. Crankcase pressure is used to pressurize the tank using a check valve, the regulator is placed at the carb and lets fuel flow when the carb demands it. Here is a Cline at the carb on a ST 3000 the check valve is just inside the backplate.

I think i understand how it works, i am curious how the crankcase pressure thing works as I dont have any holes in the crankcase, do you have to drill in to the motor? Also, the Tee from the crank to the tank, is that the overflow? If so, how does it pressurize the tank if it is Tee'd to an overflow?
Thanks,
Chris B

Chris, the line going to the left in the picture only goes about 4 inches out of sight and has a plug in it. It serves only to vent the tank while you are filling it. The tank is filled through the black line. I drilled and tapped the center of the backplate for an 8-32 fuel nipple.

Ok I understand. Thank you for showing me that. Would you suggest a cline regulator over a perry pump for the O.S 1.20AX?

Cline all the way. I have been useing them for years.

I talked with Jim Cline today and he says he started making the Cline regulator in 1990.

That it originally used the regulator parts from a Walbro WT-158. That carb is now obsolete.

But the Walbro repair kit D10-WAT has the diaphragms and gaskets to fit all the WA and WT series Walbros. Bought two of these kits at the local lawn mower shop, one for my Echo leaf blower. He says that the gasket you use with the diaphragm should be .030" thick. If not, you may have to adjust the lever. The Cline from the factory is set up to require a 3" WC vacuum relative to existing atmospheric pressure on the outlet before it will open.

He says you should keep the diaphragm sealed up at all times to prevent it from drying out and cracking. Someone in another thread mentioned putting a loop of fuel line between the inlet and outlet.