>> It runs a bit rough on idle

Can you be more specific. Does it speed up or slow down on idling? If it speeds up, the pump could be too lean, turn in 1/8 of a turn clockwise to richen the mixture. If it slows down, it could be too rich. Then, lean it by turning 1/8 turn counter clockwise.


It all depends on what fuel & prop that you're planning to use. I have been using Coolpower 30% heli with APC 20x10.5 PN prop on my 170 for a long time, the rpm is about 7,100.

Assuming your engine is fully broken in, with a new plug & the valves have the correct clearance. Start with high speed needle about 1-3/4 to 2 turn out, & the pump at flush.

Another thing to check is the valve cover. Some of them have high spot on the contact surface, leading to some air leakage. Place the valve cover on a fine 400 grit sand paper - be sure your table top is smooth - and wet sand the contact surface lightly until it's shinny. Also, make sure all of the screws are snug, not real tight, but snug.

In addition, be sure the engine compartment are well ventilated. Install foam strategically around the engine to direct cool air onto the valve cover & fins on the crankcase. After landing, use an infrared temp gauge to record temp. If your engine has the correct setting & good ventilation, it should be between 115 to 125 F, even if air temp is close to 102 degrees.

Hope this helps. If you have more question, feel free to post.

Adrian