bbbair

Ok; I have two DA 50Rs that start right up and run great on idle. They top out at 6500 RPM on the ground swinging a 22 x 8 prop, but in flight when I start to go to full throttle they 'cough' a bit and threated to die. So I bring the throttle back to 2/3 and keep on flying... where they work great.

Both engines have started doing this in the last month, the gas is fresh every two weeks, the engines are 4 & 6 years old and just nicely broken in (weekend flier) and I am still running a 32:1 mixture.

I have tweaked the engines on high and low end and had minimal change.

Any ideas as to what might be causing this 'Cough'?

speedracerntrixie

My Feedback: (29)

Could be a few things. Check your filters, the interior screen in the carb, plugs have worn to the point of excessive gap and try a new known good ignition battery bypassing any switch.

bbbair

Filters are clean, The plugs have been cleaned and the gap checked (no problems), the ignition modules have been flawless all year and the batteries are 2300 ma and fully charged before each day of flying.

I'm going to be running a fresh can of gas through them tomorrow with a 50:1 mix and see how it goes.

All Day Dan

My Feedback: (5)

When you run out ideas;

Change the spark plugs. It’s not unusual for a plug to look good, have a good spark but fail under compression.

Bypass the kill switch, if you are using one. We had one guy pulling out his few remaining hairs when he finally found out it was an intermittent switch.

Dan

nonstoprc

My Feedback: (90)

check out the two long screws that hold the carb to the engine. If they are backed out a little bit, a leak can develop.

FlipSideFlyer

My Feedback: (58)

Could turn out being ignition issues; HOWEVER, before purchasing that new ignition, CHECK THE SENSOR MAGNET! See my experience with this issue at http://www.rcuniverse.com/forum/gas-...ition-not.html and hope you're able to get it working. -"flip"-