Help with tuning new M-46 engine
 

Hey guys, i just got a Megatech Airstrike with a M-46 engine and it constantly cuts off while flying or before take off. It first started with the factory tune settings....so i tried richening the Hi-sp needle and it still cuts out when im advancing the throttle...but for the most part it runs great when the glow starter is on. please help, the manual with this plane sucks.
Thanks

RE: Help with tuning new M-46 engine
 

It actually sounds like it may be too rich. With the plane held securely, get the engine to full throttle and adjust the high speed needle until you achieve maximum RPM. The richen it a few clicks so it loses 200-300 RPM. Now bring it to idle and adjust the low speed needle 1/8-1/4 turn at a time until you get a reliable, smooth idle and nice transition to high RPM.

It's a good idea to run it to wide open throttle now and then to clear it out while tuning then check your adjustments.

My guess is that you'll have to lean the needles but not seeing the engine in person, I could be wrong.

RE: Help with tuning new M-46 engine
 

In addition to ChuckW's good advice, remember that one way of determining if you have the LS needle too rich is if the engine drops in RPM's when you remove the ignitor.

The engine should produce either NO or a very slight drop in RPM's after you remove the ignitor. If after removing it, it continues to slow down over time, the LS needle is too rich, which can result in the plane cutting out in the air when you pull off throttle.

RE: Help with tuning new M-46 engine
 

There's also the situation whereby you raise the nose of the plane straight up to check the mixture adjustment. The engine must be at full throttle.

You can tell by the way the engine runs if you are too lean

RE: Help with tuning new M-46 engine
 

Ok, with the engine at full throttle and held pointing straight up, i didnt really notice any change in speed. what does this mean?

RE: Help with tuning new M-46 engine
 

Good advice so far but I will add my 2 cents worth,
An engine with a too rich low speed setting will load up fuel in the crankcase. So when you open the throttle the engine sucks all the excess fuel and sputters or dies. Also if you are wide open no fuel will build up until you reduce throttle and the build up begins causing rough running or dying.
So set the High speed as instructed. Let the engine idle a while then open it up (not to fast) if it sputters and goes rich or dies turn the low speed setting clockwise a LITTLE BIT like a 1/16 of a turn or less. restart and retest. The closer you get to where yo uwant it the smaller the turns, this process is a PITA. But doing it right will give you a great running engine. Also be aware that an engine that has not been run in adequately may not take the leaner iddle settings yet. Some engines need 3 tanks or so some need a gallon.

Make any errors on the rich side! Because it is hard as heck to put aluminum or chrome back on a cylinder wall![:@]

A day at the field when it is to windy to fly is a great time to run in and dial in a new motor. Running one in while others are flying is sometimes not so well appreciated. go to the far end of the pitts if others are flying. Some fields have designated run in areas.
Do a search here on engine break in and ead up.

RE: Help with tuning new M-46 engine
 

At that moment your mixture was ideal

In cooler weather the engines seem more sensitive to the air aloft when flying.

The Alcohol/Nitro air-fuel ratios are much richer than gasoline and therefore the temperature difference changes the mixture requirements considerably.

I always have to make them a little richer from the peak point in the winter than in the summer

Some people adjust their mixture with the nose high

RE: Help with tuning new M-46 engine
 

OzMo gives good advice

RE: Help with tuning new M-46 engine
 

Hey, the plane runs great now, thanks to you guys!

RE: Help with tuning new M-46 engine
 

Wow... we did something right for a change.