Ekvien

I recently purchased a used 170 but struggle to fine tune the engine. It runs a bit rough on idle and after some minutes in the air its starts to have trouble with transisting from idle to full throttle. What is the basic settings both for the pump and the high speed needle?

Any advise is highly appreciated

riot3d

>> 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

Ekvien

Thank you for your advise Adrian. There were several minor issues, like pump settings (to lean) high speed needle (to rich) and lack of filter clunk. 5 flights last evening without any problem

Ekvien

In accordance to the manual the tappet clearance are only 0,002 mm!!! how could you be able to measured that clearence ?

Ekvien

Sometimes it is smart to read with the glasses cleaned, the tapped clearance was in inch not in mm

riot3d

I never use a feeler gauge, just by feel. Basically, no movement at TDC. I check them about 50 - 60 flights.

Adrian

drac1

My Feedback: (4)

If you can't feel any movement, then there isn't any clearance. Even with 0.002" (0.05mm) clearance, there is noticeable movement.

Ekvien

Have adjusted the tappet clearance to be 0,05mm, it was no clearance at all so hopefully it make a smoother running especially on idle. Also changed the gasket for the valve cover. Will be flying later today so I will soon find out if everything is 100% settled now.

Ekvien

6 flights today with smooth idle Now it's running like I want it to be. Fuel consumption is definitely lower and also the battery consumption, mondays flight was about 110 mAh pr 8 minutes and today it was less than 70 mAh pr 8 minutes.

Now I'm ready for the Norwegian Nats