PlagueWielder

Hello,

I have a new (around 3 weeks old I think) OS .46AX that only had around 10 flights so far. It has worked flawlessly until last weekend. The problem is that if I put the stick in around half throttle and engine cant keep the RPMs and just slowly drops until it dies. The only way to stop it from dieing is to bring it back to idle. Now if I go from idle to full throttle instantly the problem doesn't happen. Also, it doesn't do this in any other position, just around half throttle.

What we noticed is that very little fuel is coming out of the idile needle valva where the arm connects to the carburator. We are going to open that up and check if anything is worn out inside.

Do you think this could be the problem? Or what?
What could cause this problem? Im running an APC 12.25x3.75 and mostly fly at half throttle or less (TopCap). I don't think it's because of the prop or anything since I've used it on .46FXs and .40FX in the past..

Thanks

roltech

Who knows? I had a similar problem with a OS46FXi could not figure it out, so I took the engine to the hobby shop and they kept it to check it out. in the meanwhile I bought a OS46AX and had the same problem I took the gas tank and all the gas lines and replaced them with new, but same thing. I could not believe what it turn out to be .
The glow fuel! I had about a quarter of a container left and went bad maybe to low on nitro? I pumped all the gas put and a club member let me use his gas and there it solved the problem. ran fine right off the bat. so sometime we try many other things and it could be as simple as bad gas, I picked up my OS46FXi and re install to the plane before the hobby shop had a chance to check it out and sure enough it was ok too.
Not saying your problem is the same but the symptoms are alike, hope that helps.
good luck

roltech

PlagueWielder

I don't think that's the solution to mine because we usually run the engine with 12% fuel and at the field before giving up we tried some 5% and it did the same.

I will try someone else's fuel though, maybe all of my fuel is bad somehow... you never know.

Thanks!!

smedsky

I doubt if nitro has anything to do with it. It sounds like it is lean at mid range so richen the idle adj just a little and if that doesn't help flush out the carb and start over.

PlagueWielder

Will try as well. Thanks

Any more suggestions?

MinotRich

Did you have a hard landing before the trouble started? I too have been frustrated by problems like yours. Turns out that the "clunk" line got thrust forward in the tank and the engine was barely able to draw enough fuel to keep it running. I would try removing the tank and checking the clunk. If that doesn't help, try replacing the tubing while you have everything apart. Might not hurt to flush the tank with some rubbing alcohol too to get rid of any "crud" that might be in your system. Also, try blowing through your tank and lines to make sure there are no obstruction in your fuel system. After that, if you still have the problem, try some new fuel. I had an O.S. .52 Four Stroke engine last year that would not run at the beginning of the season, but ran fine the season before. It was stored over the Winter months and I added a few drops of after run oil at the end of my flying season (good habit to get into after all runs, in my opinion). Turns out my old fuel just wasn't cutting it, so I tried new fuel and my problem was solved. After I ran a couple of tanks of the new fuel through it, I just mixed the new new and old fuel together and I didn't have any more problems.
Hope you get it running good soon! Spring Fever and Flying weather is finally here!

PlagueWielder

Well actually I did have some hard landings a week before (damn wind). I actually thought about that but someone at the field said that that's not it. I'll go and look in a minute.

Thanks.


Edit: Well that metal piece is free in the tank so that's not it. I'll try to fire up the engine today with some other fuel and we'll see if it's the fuel.

Kaos Rulz

PlagueWielder

I experienced a similar problem just this weekend with a GMS 120 mounted horizontally. We checked everything and found out that it would run OK at the mid-range only by leaving the Ni-starter on the glo plug. So we surmised the plug was being washed with raw fuel at that setting and cooling the coil down and causing the engine to die. We put an idle bar type of glo plug in and the problem was cured.

Might be worth a try. See if you have the same problem with the Ni-starter connected.

PlagueWielder

We tried that at the field and it did the same...

Thanks