Antsis
08-16-2006, 11:09 AM
Hi Guys
I'm not too sure if this is something serious or not. I have the PS on my predator with the Century 90 size silent pipe and have probably put about 2 gallons of fuel through it. I started with Magnum 20% and, when I couldn't get it for a while, switched to the Century heli juice 20%. Because the engine was new, I ran it about 2 turns on the main needle and slowly reduced this until it was about 11/4 turns.
Anyhow, when I go from the hover to FF, the engine note doesn't change much and it also doesn't sound like it's struggling. About 5 minutes into the flight the engine note changes, speeds up and the model becomes more lively. The fuel level is about halfway between the bung and top of the tank when this happens. The transition is smooth with no sign of four stroking I would expect with a rich engine. I've felt the pump after landing and it does not feel unduly hot as if the engine had gone lean.
I have three lines on the tank:- feed to the carb, return via the check valve and return from the muffler. Is it possible there's too much back pressure from the muffler causing the engine to run slightly rich at first?
I'm not too sure if this is something serious or not. I have the PS on my predator with the Century 90 size silent pipe and have probably put about 2 gallons of fuel through it. I started with Magnum 20% and, when I couldn't get it for a while, switched to the Century heli juice 20%. Because the engine was new, I ran it about 2 turns on the main needle and slowly reduced this until it was about 11/4 turns.
Anyhow, when I go from the hover to FF, the engine note doesn't change much and it also doesn't sound like it's struggling. About 5 minutes into the flight the engine note changes, speeds up and the model becomes more lively. The fuel level is about halfway between the bung and top of the tank when this happens. The transition is smooth with no sign of four stroking I would expect with a rich engine. I've felt the pump after landing and it does not feel unduly hot as if the engine had gone lean.
I have three lines on the tank:- feed to the carb, return via the check valve and return from the muffler. Is it possible there's too much back pressure from the muffler causing the engine to run slightly rich at first?