i'm not talking about a small amount of gas in the oil. i would have to say there is about 1-2 liters in the oil. i did an oil change less than 2 weeks ago. i am guessing that the diaphragm in the mechanical fuel pump has a hole in it or something but i was more so wondering if this could have been caused by the return line not being hooked up. i would definitely not want this to happen again if i do replace my fuel pump.

 

A diaphragm pump is a positive displacement pump and the fuel that is pumped and not used needs to go some place or the system will over pressurize. If it can't return to the tank when proper pressure is reached, as per design, the diaphragm will receive higher than designed pressure and will be prone to premature failure. Usually this problem will give drivability symptoms and/or leaking at the carb.

 

that makes sense. my truck has been having problems and the plugs have been ending up black.

 

Not to be smart assed but what about all the years they did not have return lines?

 

This has always been true but no one gave it a thought. Someone finally thought about it and decided to add a return line and everyone adopted it. Improvements only come when someone thinks there might be a problem and then finds a solution.