ORIGINAL: jimmyjames213
RCken wheres the pic?
I haven't given him this one yet
This is an excerp from the article I wrote on tanks. [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=1068]Click here for the rest of the article)[/link]:
At any time you may experience problems with your fuel system. Here are some of the more common problems and things to look for.
One of the first things to look for in any situation is any sign of bubbles. Not all bubbles are bad, but you should know the bad ones from the acceptable ones. The first type of bubble is just a little foam that may accumulate in the fuel line (Pictured on top of illustration at left). It is usually just sits in a high spot in the fuel line and it may or may not have much movement. Pictured at the bottom of the illustration is a line of bubbles that are moving from the tank to the carb. This is a definite sign that you have an air leak somewhere, and it needs to be corrected.
An air leak is usually caused by a bad connection, a pinhole in a line, or a malfunction in some apparatus (Like a fuel filler or remote needle valve). Now it's time to do a little detective work!
Start by filling the tank. If the bubbles appear while the engine is running with a full tank, you can pretty much figure that the leak is outside of the tank because all of the tank's internal components are surrounded by fuel (That's a good thing - you don't have to take the tank apart!).
The next thing to check is the line from tank to carb. Is there anything between the two, like a fuel filler or remote needle valve? If so, do the bubbles start before or after it? These are the types of questions you'll need to find the answers to. For instance, if there are no bubbles from the tank to the filler, but the bubbles are seen between the filler and the carb, replace that piece of fuel tubing. If the bubbles persist, your fuel filler valve is leaking air.
If the bubbles only appear at a time when the tank is less than half full, then the leak is most likely inside the tank. The easiest remedy is to replace all of the internal tank lines.