Hi All,

I have an Evolution .52NX nitor motor that seems to be leaking from the carb when I am filling the fuel tank. I have gone over all the fuel lines, tightened all bolts and still have the leak. The plane has been stored for about 6-8 months and was thinking that maybe the seals or gaskets in the carb are shot. Would any of you have any trouble shooting tips for this situation or any experience with these motors?

I appreciate all the help,

C-Mac

Are you sealing off the flow of fuel to the motor, when you are filling up?

In other words are you somehow DISCONNECTING the motor, when you fill the tank?

If not, it does not sound like anything is wrong.

If you do not at least clamp the line, glow fuel WILL leak out ( or into ) the carb while fueling.... e.g. if you use a "T" connector, etc...

Thank you for the quick response but that is not the case. I have fueled a few nitro planes in my time and have never encountered this issue.

Well, I have several engines that I have not run for the past couple of years and none of them leak like that. I usually fill my tank from the engine supply line rather than from a third "filler" tube, however, one engine has three lines (vent, fuel supply, and tank filler).

As a bit of an add-on to what Opjose suggested, try this: make sure your throttle is completely closed by setting the trim to minimum and the throttle stick to completely closed, then try to refuel. See if it still leaks.

CGr.

Even if you have the throttle body completely closed, the needles should still permit slight fuel flow.

You didn't say if you closed off fuel to the carb as I had asked...

But if you do not, you are pressurizing the line to the carb and FUEL WILL FLOW into the carb, albeit in small amounts.


Sorry CGRetired, but I beg to differ... you can try hooking up a piece of clean tubing and blowing into the carb nipple.

If the engine is properly tuned even at almost full throttle closure you get a bit of air flow, as NORMALLY the needle does not fully seal the aperture. There may be exceptions to this, but usually people fuel with the engine set to idle or there-abouts, so they can see fuel dripping from the carb if they do not clamp off the line or disconnect it.

Remember that they are effectively pumping fuel INTO the carb.