my 46AX dead sticked tonight again. I bought this engine new and broke it in like the book says. The first time up it ran fine. Then I took it up and it started cutting out, and then dead sticked before I could get it down. My clunk had came off the fuel line[X(]. I pulled the tank and replaced the line and the clunk, put it back in and took it out tonight. I started it up first flip and it sound like a 4 stroke, like it was bogged down. I pulled the idle down and noticed the prop was spinning backwards. but I've read here that it's not a big deal, so I pulled the idle down and then up quickly and then back down and that fixed that problem and the engine began to scream like it should. I took it up ran it around 10 mins and decided to do some touch and go's. brought it down landed smoothly and back up. Once I got it back up it started to cut out I tried to loop back around to line up to bring it down and the engine lost all power, just a idle, then dead stick. Got it down. the clunk is fine, I restarted the engine. it was bogged down again this time it took a little time running before it ran right. It did began to run right I made sure the engine was not to rich but still on the rich side. The engine ran fine now on the ground so I took it back up and with 2 mins it dead sticked. I'm not sure what the problem is, It has new fuel line in the tank, I'm going to put all new line on the outside too. What do you guys think?

Tuning issue. Did you have someone at your club help you? Sounds too rich to me. How many turns out is your needle? Are you sure you're counting 'full' turns?

You should start from scratch; while the engine is off, close the needle all the way (don't crank on it, just until it stops turning) then open two and a half 'full' turns (to the left) and start the engine. This would be a very rich position. Turn the needle SLOWLY to the right, a few clicks at a time (make sure you realize what a click is, a guy at my field kept turning like a quarter turn at a time. Literally one click) until you get to peak RPM, or at least what sounds like a plateau in the increasing of the RPM, then richen 4 clicks or so. Check by pinching the fuel line to the carb; a brief pinch and let go. The engine should speed up when you pinch the line. It it wants to quit, you are too lean.

How many tanks of fuel have been through this engine, is it pretty new?

Also have you touched the idle mixture screw?

the engine has about 5 tanks through it, its still new. I have'nt touched the low speed at all. I did get the high speed to sound right. 3 or 4 clicks rich from peak rpm's. Yes I do know what a click is. Could this be a low speed problem. I have'nt touched it. it idles nice. I have'nt had anyone else look at it yet. I may end up having to get someone to check it out.

I would suggest not touching the low speed. They come a tad rich, but not enough to cause you any problems. I finally tweaked my low end last week, after running 4 gallons of fuel through my engine.

I had to be shown how to properly tune an engine, despite how much I read on this forum. Now I'm pretty good at it. You'll get the hang of it

thanks. I'm sure its a tuning problem , I am new at this, about 5 months. I've gone about this mostly at my own with reading a lot on here. But I do have a guy that I can go to and get help.

You are going to LOVE that engine when you get it set up right. I won't even consider another brand now. I just got another (55) AX.

Before you go messing with all the needles, try a new plug. It is possible for the plug to still work, but not efficiently. That is the first thing I change when one of my nitro cars isn't running right. Try that and retune with it. Give her a flight and see how she does then you'll know if its the plug. That is the first thing you should always change when you can't get it to run right.

Has the engine ever been running right? With only 5 tanks and chronic dead sticking it doesn't sound like it.

Three things to check. In order of simplicity
1. glow plug
2. air leaks/ tank pressure/ tubing
3. tuning

If 1 and 2 dont fix your problem you might try and lean the low speed a tad. If its idling then bogging when you give it gas its probably loading up a lil.

I would consider the plug as well,mine came with a OSA3 plug which is great for the break in,since it runs a bit hotter,but after several tanks my plug began to foul and the engine ran poorly,durring break in metal shavings can foul plugs rapidly once this is over the life of a plug is quite a bit longer.
after switching to a OS#8 its a smooth runner,my needle is set about 1 1/2-1 1/3 turns on the HS needle,2 1/2 turns is a bit rich for the 46 AX 2 turns is a good starting point,I am just starting to notice the low speed bogging that comes with a fully broken in engine,after several gal of fuel, its time to lean out the low speed needle.
if you are not comfortable with this then a little help goes a long way for tuning, since just a small turn is usually needed on the low end.

You can change the plug if you want to, but it sounds like the low-end is rich to me. The symptoms you've described are pretty classic (Dying at idle and starting backward)

Try this:

Start the engine, bring it to full bore and let it run for a few seconds at peak RPM. Now bring it to full idle.

Once it comes to full idle, it's not unusual if the RPM drop a LITTLE more, but it shouldn't drop a whole lot. Keep letting it idle. If the RPM continue to decrease or if it dies, chances are it's rich on the low end.

A good way to check is...

After it has been running at idle for at least 15 seconds or so, pinch the fuel line close to the carb with a pair of long-nose pliers (Or pull it off completely at he Carburetor) It should run for a few seconds and increase RPM slightly and then die within a few seconds. IF it continues to run for more than a few seconds with a noticeable increase in RPM, it's rich.

To adjust it, (With the engine NOT running) turn the idle screw (On the Right-hand side of the carb directly opposite the needle valve) 1/8 turn clockwise.

Now open the high-end needle about 1/4 turn, start the engine, bring it to full bore and re-adjust the high-end needle.

Now, repeat the test. Also check the transition - After it has idled for a few seconds, zip the throttle up quickly. It should respond almost immediately. If it lags but eventually comes up to peak, it's still rich - try another 1/8 turn in on the low-end needle.

Mike: Starting backwards. My .75 AX starts up backwards about 50% of the time. I usually just tap the throttle and it goes the right way.. but it does start up backwards very often. I tend to tap the prop with the chicken stick in the reverse direction, but never to the point where it goes beyond compression, I usually let the compression push it back forward and it starts up, first flip every time.. however, often backwards.

Would that be the low end mixture again??

CGr.

CGr,
More often than not engines start backwards becasue they are overprimed.

Ken

Exactly. Which is why I suspect his low-end may be rich.

If an engine dies at idle, and (Without priming) it starts backward, that's a good indication that it has too much fuel in it. Hence, the low-end is rich.

Millertym,
Are you dead sticking only after you bring the throttle down near idle, maybe the lower 1/4 of the throttle range? Or does it happen when the engine is running in the higher rpm range? I was under the impression that your dead sticks were happening with higher rpms, but now reading it happened after touch-and-gos, you were probably down near idle and getting bogged down by the low end valve.

If you have your plane on the ground and get the engine running up in the higher rpm range, play with the throttle, keeping it over half throttle, and see how it works, then bring it back down to idle and let it idle for 20 seconds, and try to advance the throttle again. If you're running fine at higher rpm and only having problems when you go back down near idle, than it is the low end valve. If you're having problems at higher rpms, half throttle or above, then it's high speed needle.

If it's low end (happens when you go somewhere near idle then back up) you can turn the tiny screw inside the throttle arm (1/8 turn increments) clockwise, with the engine STOPPED, then re-tune your high end, and see how it works. A small change on this screw makes a big difference, so do it little bit at a time.

Didn't I already say that?

I also have a new OS 46 AX that I put in my well-worn trainer to complete the break-in process. Compared to the Thunder Tiger .46 Pro I've flown for the past 4 years in the trainer, the 46 AX pretty much starts instantly. I still have issues with the TT starting/running backwards. On the AX, I simply hit it briefly with the starter and it's running.

Also be advised the AX has a rear-mounted remote needle. There is a bit of a lag from the time you adjust the needle until the engine recognizes the change so be patient. I use the stock A-3 plug and didn't change the low speed needle and also had pretty consistent deadsticks. It didn't help that my low end servo limit isn't quite set up right.

I began closing the low speed needle about an eighth turn at a time and have the idle and transition better but there still seems to be a pronounced midrange richness I've not yet been able to tune out.

I just sold my beloved trainer so will have to complete the tuning on the intended Somethin' Extra ship once I complete the build.

Ok. the engine was dead sticking at 1/2 to full throttle. I did change the plug with no change. when I primed the engine I turned the prop 3 turns and it was FULL. I had to turn it over and let it all run out. So I tried 2 turns and it stilled flooded it. So I went to just one turn to prime it and it was ok. Once I got it started it was acting like it was really rich. After running a while it would clear up and run fine. I'll do the pinch test on the carb line and see what happens.

Oh yeah!

I think the word "screaming" in your post is a clue.

Hey me too!

hey guys, I think I found my problem. I started the engine today and it would idle only. When I raised the throttle it cut out and would die. It would idle for a little bit then die. I pulled the carb to make sure it was clear and didn't have anything in it. I blew through the fuel intake line and it felt clogged. I ended up blowing a piece of dirt/grass something out of it. I put it back together started it up, tuned the high speed a little and it ran like new, I just need to take it up now thanks for all your help.

Well there you go. It was runnin rich...

Millertym, I'm glad you found it! Nice job. (I knew it wasn't the idle mixture )