hello everyone... so ive got an evolution .46NT engine on my plane, still a beginner, on my 3rd plane...destroyed the other 2 with this engine on them. haha yeah but the engine still runs pretty good! ive taken it apart for cleaning, but only the basic parts such as the carb, high speed vavle, muffler. i cleaned inside where the carb was and inside the cylinder through the hole where the muffler goes. so i dont THINK i couldve screwed anything up that way. im prob wrong but anyway. ive had this engine on my new plane for about 5 flights that went perfectly fine except for the glo plug goin out on me. i put a new one in and flew a couple more flights. today i go out to fly and after starting the engine i go to take off and engine cuts and my plug is bad again. so i start it again and let it idle with the glo stick on it....BUT THIS TIME, THE PLANE STARTS GOING BACKWARDS! being a newbie i didnt even know this was possible. so i start it again but this time i flipped the prop the opposite way to start and it pulls forward again. just to make sure i went backwards and forward and sure enough the plane was pushing back or pulling forward depending on which way i threw the prop. SOOOO.......
can someone tell me how, why this is happening and if there is anything i can do to fix this. also is it dangerous to fly at this point, assuming of course i started the prop clockwise to make it rotate counterclickwise...pulling normal. HELP!!! IM BROKE AND CANT AFFORD A NEW ENGINE!!!! K THANKS

It's not that uncommon to have the engine start backwards. It's never happened to me so I couldn't really get more specific than to say that from what I've read, when you start your engine try to keep the starter on the spinner for some additional seconds to make sure its turning in the proper direction.

Evolution engines, in my experience seem to run backward more often than some. Generally, it is because they are running too rich. Close the low end 1/4 turn and start with a starter as opposed to a chicken stick or finger. One more thing, if by chance you have a three line fuel tank setup, clamp off the line going to the needle valve before filling the tank. That will keep excess fuel out of the engine.

Happy Landings!

I also have probs with my la 40 and ax 46 I use a starter and chicken stick but every once in awhile it will run backwards,The funny thing is I see no one else having this problem at the feild.Is it really cause it is to rich?

I use a chicken stick, and more often than not my engine starts backwards. I have a throttle kill switch on my Tx, and tapping that will make the engine 'cough' and it will start itself running the right direction. Haven't tried playing with the low end yet, so maybe that might be an answer. What is happening is 'hydro lock' where there is a bunch of fuel in the cylinder and not enough energy to compress it to ignition, so it stops the piston abruptly, and the reaction forces it to spin the opposite way. Another thing to try is a 'running start' where you turn the prop clockwise until just before compression, then flip the prop, giving yourself some resistance free movement to build up momentum into the compression stroke.

If you're using a starter, feel free to push the starter on the cone and hold it there, firmly, until you know the engine is running well.

The most usual cause of engines starting in the opposite way is because of over-priming. This can happen from fuel syphoning from the tank if it's left to sit for a while or possibly the refueling pushes some fuel through the carby. Normally it's simply from priming too much though. It's not dangerous to the engine and pinching the fuel line to let it use up the excess fuel that's inside the crankcase will cure it. If the engine stops then don't prime it anymore, just flick it or give it a bump with the starter.

Absolutely. When I've seen it happen the pilot had always overprimed.

I have a Evolution 61nt and it starts backwards almost half the time. it seem to stop when the engine warms up though.

Guess that means too rich!!!!

Quite common when using hand start and some engines more than some others because of port timing.

As Nathan, Grey Beard and downunder indicated an excessive prime will aggrivate this. Some folks deliberately prime to this state and always start by reverse bumping of the prop on certain engines. Some can even be started by just reverse twisting by hand of the prop spinner. I do normally recommend however for newer folks to use a starter as they become more experianced with their engine they can try other methods.

So what's the agreed upon method of priming an engine, so as not to over prime?

My .46 starts backwards a lot. I just blip the throttle up and down and it usually kicks in the right direction. Just becareful you dont get it turning the right way and the thing is coming at your fingers

oh and It does help to start the plane in the opposite way you normally would (counter clockwise). So flick it clockwise and see what happens

It has all been covered in this thread.

http://www.rcuniverse.com/forum/m_70...tm.htm#7044287

Starting a 2 cycle engine is easy once you know the technique.

So cover the carb with thumb, turn prop until you just see fuel entering the carb, insert glow ignitor then tightly grasp propeller and push through compression stroke, and start flipping with stick once there is no 'bump'.

Do you stop priming when you just see fuel enter the carb, just before, or a spin or two after?

I can't say I love the idea of gripping the prop with the engine full of fuel and the glow ignitor in place.

It kind of depends on the engine and installation. Some engines like a couple of turns choked with a couple of flips before you hook up the glow plug. You have to learn what combination works best for your engine.

As posted in the other thread, as long as the engine is open port, it will not do anything while you are grasping the prop. Hold it firmly and pull though compression and feel the bump. If it is over primed it will bump every time assuming it has a good hot plug. When it bumps every other time, it is perfect for starting. If it doesn't bump at all, it is either very flooded, completely dry, or the plug is not glowing.

Also it works best if you adjust the prop so that it is level when you are against the compression in the direction the engine runs. This makes it easy to flip and saves props should you dead stick.

my 46ax starts backwards almost everytime I go to the field. . It does it alot. I use a chicken stick.

If you blip the throttle at idle the engine will often begin spinning correctly.

Yep, this is what happens to me (46AX) and this is what I do to correct it. Was just wondering if there was something to do to get it to start the right way, though I don't mind too much as it does start on the first or second flip, just the wrong way.

Yes, I always blip it to correct it... but i'm trying to understand why it starts backwards majority of the time. I would like to to start right the first time. Is this side effect of the chicken stick?

quote]ORIGINAL: n19htmare

Yes, I always blip it to correct it... but i'm trying to understand why it starts backwards majority of the time. I would like to to start right the first time. Is this side effect of the chicken stick?
[/quote]



Yes it is a side effect of using a stick with some engines. You can either flick it backwards on your first start and it will be running forward or you can use an electric starter.

John

Well today I primed less than usual (OS 46AX). I primed until fuel ALMOST reached the carb, then 2 or 3 flips with the stick and it started in the right direction. Clearly the problem is due to excess fuel in the cylinder causing a hydrolock that we are not able to flip through, so the engine starts backwards.

N19htmare, try priming less.

You will know when you have it - one flip starts.

Yep, that's what I said above.

Yep, ya did. Thanks! Problem solved.

Then you get into planes with cowled engines and you can't see the fuel or get A finger on the carb or muffler, it's always something isn't it.
Most of my glow engines are four stroke and hidden under A cowl. I have learned over time that there is A squishy sound they make when they are ready to fire and other then the winter months they start right up every time. My YS engines are the engines I learned this from, because of the pressure system they use that sound is the key to always getting them to fire with the back snap the first time. They only give you one chance to look cool before you have to reach for the starter.[8D]