The issues I had was the the fuel pump did not like being mounted on the back of the engine. The engine vibration and engine heat caused the gasoline to vaporize into gas bubbles that played havoc with the engine running smoothly. So having the fuel pump mounted nearby and protected more from the vibrations and heat cleared up that problem. I have two different NGH fuel pumps and both of them did not like being mounted to the back of the engine directly. They both exhibited the same gas bubble problem when I did mount them on the engine right behind it.

The carburetor is a NGH design. It is quite similar to a small Walbro carb but the carb and the fuel pump have been separated into two units instead of one integrated carburetor unit. The carb is a floatless design that uses a valve that is controlled by a diaphragm to handle the fuel demands of the engine. The valve and diaphragm inside the carb sort of serves as a pressure regulator for the fuel going to the carb. But the diaphragm is really acting more like a float in a carb and controls the fuel inlet valve aloowing fuel into the carb for the engine. The fuel pump simply provides the fuel for the engine. At full throttle the engine can draw fuel from the fuel tank without the pump operating off of crankcase pressure from the engine.

The other issue is that the engine instructions are correct, Idle speed is a little under 1/2 throttle at about 1/3 throttle. Full throttle is like normal with it fully open all the way. So you need to adjust your throttle servo end point adjustments to take that into account. The carb or engine tends to spit fuel out of the carb at low speed, quite a bit too, so be prepared for some messiness there. It cam be a bit difficult to get the fuel pump going so the fuel is being pumped so using a electric starter to get it going is a big plus. After you have it running some OK and dialed in better hand flippling the prop to start it is no problem. You can actually see it spitting fuel after 1 min and 20 seconds of the first video I posted below here.

You want to use the small spiral spring wire clip for the base of the spark plug cap, it really does help lock the spark plug cap onto the spark plug. I didn't use it when running the engine on the test stand, but after a while the spark plug cap tended to want to come loose.

In the airplane pic where I show the RCexl ignition module inside the plane, I actually used velcro to fasten the ignition module into the plane. the velcro helps dampen engine vibrations and isolate the module from the vibrations but allows it to be open for air circulation so it doesn't overheat. You can't just wrap it with foam padding and stick it inside the fuselage as it will over heat if you do so.

I used black neoprene rubber tubing for the crankcase pressure fitting to run a tube to the fuel pump. The Tygon tubing became soft over time and would slip off the engine pressure fitting. But the black neoprine tubing doesn't have that problem. The neoprene tubing tends to naturally glue itself to the pressure fitting, so it tends to stay on there much better.

You do not have to use the stock in cowl muffler that comes with the engine. A OS 46 style muffler fits oK too. I used a Mac's one piece muffler designed for a OS 55AX engine on my NGH 9cc engine and it fits just fine. The screw hole spacing and exhaust outlet supports a wide variety of different mufflers and brands that will just bolt right on no trouble.

I also didn't want to take any chances with our modern ethanol laced gasolines here in the USA causing the rubber parts inside of the fuel pump or carburetor causing problems. So I used the Tru-Fuel or SEF fuel which is a more simple, non-ethanol gasoline in my engine. I really like the stuff as it leaves little to no gasoline odor or smell behind. Our ethanol laced gasolines simply make me a bit nauseous and it stinks up the house if I bring a plane or engine inside to work on it. My family quickly starts complaining about it. But the Tru-Fuel or SEF fuels are great, it doesn't stink up the car or home. Tru-Fuel is sold at Home Depot or Lowes and the SEF fuel is made by the Powermaster fuel company and it can be found in some of the larger hobby shops too. The fuel is more expensive than pump gasoline though. So that could be a detractor against using it for sure.

Here are a couple of videos I made when I was running the engine.

[youtube]http://www.youtube.com/watch?v=PlwJAU3fnUw[/youtube]

[youtube]http://www.youtube.com/watch?v=UKGoRC2hWaE[/youtube]