No they can start backwards....

The reason you have a problem is there is some dirt or debris in the regulator. The fuel leaking from the carb is because the regulator is not closing.

YS engines do not suck fuel they are force fed fuel from the pressure in the tank. The regulator does just that regulates the amount of fuel that gets past. If fuel is spitting from the carb like you say and it just ran fine...you got some dirt in the regulator and its sticking open. This is likely under the adjustment screw keeping the little plunger stopper from closing.

Filtering your fuel 2 3 or even 4 times is a good thing and can prevent this problem. I filter in the bottom of my fuel jug, then I filter at the line that connects to the model to fill it and I have a filter in the model as well.

A small little flake of anything can cause this problem.

You need to remove the regulator and flush it out with raw fuel. As I said the dirt is probably under the stopper. to get to this portion remove the regulator adjustment screw making a note where it is referenced from flush with the housing of the regulator. The clean everything with raw fuel nd put it back together. This needs to be done in a dry clean place...a small piece of lint could easily be the culprit.


Troy Newman
Team YS