I have not used this engine in several years. I replaced the electric fuel pump inside the vapor separator. The engine idles fine and runs upto about 2500 rpm, then it starts cutting in and out like the fuel is cutting out. In the very bottom of the unit under a plate is a small $200 part call a surge device. Not sure it I need to replace this and at $200 cost would like some way to test if this is the issue. I wish they made is easier to work on, take half the thing apart to change a fuel pump.Any ideas what my problem might be?