RE: Help a newbie tune his GST 7.7
Actually, you will need to lean both the high side and the low side, But start with the high side and once you can get it running again you will need to lean out the low side to help control the fuel pressure. The Checkvalve actually increases the pressure in the tank and holds the pressure more consistently, and before the checkvalve the fuel pressure variation was controlled by exhaust pressure and when you let off the throttle the exhaust pressure would drop so the low end needle needed to allow more fuel in to stay running so the low end needle was "wide open". Now with the Checkvalve in place the fuel on the low end side is controlled by the needle instead of lower Exhaust pressure, so you will need to lean the low side needle.