Zenoah 20 cc motor RPM problems

[mynzbtr]

I have a Century Radical FBL. It has a Zenoah 20 cc motor in it. At idle the motor sounds great very little smoke, Running smooth so I figure I have that dialed in. As soon as I get her into a Hover (not at idle up yet), but a good hover, you here the RPMs start to go up. I am no increasing throttle. The motor did not sound right. After that occurred my bird leaned to the right and went down. I'm thinking the vibration in the motor after the increase in RPMs cause my ar7200bx to go nuts. Is the motor to lean on the high end ? Or am I missing something. Any help would be greatly appreciated.

[sctholson]

Is this a new motor? Have you watched Tom Welch's tuning video?

Carburetor Tuning Part 1 with Tom Welch (10 min 17 sec)

Not sure about leaning to the right, but it sounds lean at idle, there should be smoke. What are your needle settings?
Has this heli ever flown before?

[gassed]

your are not giving us much information to go on.

RPMs go up and heli tilts to the right and goes down could be anything from a FBL failure or a swash link came off or a RX power failure or just lost signal to the RX and you didnt have a fail safe programmed.

I would rule out your RX and FBL system first then go to tuning the engine...especially if the engine had been running fine before.

when testing an engine in a heli you need to be 100% sure that the RX/FBL system is working and is programmed correctly.

[mynzbtr]

Thanks guys for getting back to me. The settings on the needles are pretty much close to factory. And no, its not a new motor (used). As far as the set up, swash plate and receiver its spot on. I'm very familiar with the beast x. I made two flights with this bird, no problems. When I took it up for the third time is when this occurred. (now that I'm thinking about it I do believe I might have made a slight adjustment on the high end before the third flight). Maybe to much ?. It just seems to start to scream for no reason. And when it does that, it throws off the beast x (vibrations). Causing it to lean. I haven't looked a the video yet but I will, thanks. I was just wondering if anyone had experienced this before. I did read that if the motor takes a long time to settle in at the high end it could be lean.
Thanks again
Nick

[SlezY83]

Do not you have same/similar problem like I am dealing here:
https://www.helifreak.com/showthread.php?t=701408

- check my videos, which I made and compare it with your behavior.

I am interested what could be problem because it sounds EXACTLY same like my one.

Roman

[fastflyer20]

Sorry to hear that it crashed.

Beastx does not like vibes, IMHO it is not the best choice for a gasser.

It sounds like it is going lean. Two possibilities are that the needles are not set right or you have an air leak. Buy a can of Dust Off used to clean electronics. With engine idling, spray the gaskets around the carb insulator. If the engine decrease in RPM you have an air leak.

I just had a good one, engine was running erratic. Sometimes the gov seems to work, other times the RPM's would be too high. The Dust off test showed an air leak I installed new gaskets to seal the carb but it still failed the air leak test. Then I noticed that when the heli was tilted it would also go lean. I changed out the carb and now it is OK.

Step 1. Increase the low needle 1/8 of a turn and see if it is better. Return to original setting if it does not help.
Step 2. Increase hi needle 1/8 of a turn and see if runs better, if it does. Increase another 1/8 of a turn and then do a test flight.
Step 3. If increasing the needles does not help, test for an air leak.
Step 4, If the insulator is black plastic, replace with an aftermarket aluminum that uses thick Teflon gaskets.
Step 4a . If there is an air leak and you are already using an aluminum insulator replace insulator gaskets,
Step 5. Repete air leak test. Note that It is normal if RPM's decrease when the carb shaft is sprayed.
These steps solve 95% of lean issues.

If the engine is still showing signs of being lean you may have an air leak from a seal (typically the flywheel end), the crankcase gaskets or a bad carb. If the piston was damaged due to it being too lean it will not run right, pull the muffler and look in exhaust port to see if there is damage to the piston.

[mynzbtr]

You guys are great. I got some work ahead of me thanks.

[rbort]

The G20 has a different carb than the RC or PUH motors and has different needle settings. Not sure what "factory settings" you have, its been a while since I owned my Radikal G20 motor, but IIRC the low needle is open more than the high needle for this motor.

If you search my posts on runryder I might have mentioned the needle settings on this heli there somewhere.

-=>Raja.

[SlezY83]

I would like to ask you what is your configuration EXACTLY. I mean parts like:
- governor
- sensor for governor (what is source of pulses for gov if you use it)
- ignition (electronic vs magneto?)
- receiver
- battery(ies)/generator
- kill switch (if you use it)
- on/off switch

Because I would say, that I am close to end of my investigation. Not sure now, but I would say, that I am close (I have to confirm it)...

Roman

[mynzbtr]

Not using a governor, only kill witch is the throttle hold switch and im using a 3000 mah receiver battery for both the EI and rx. (Ar7200bx.) I'm thinking insulator . I am also using a (Ultra IBEC) from tech aero designs that eliminates any interference from receiver and motor.