My Zenoah G20 PUH runs like Crap

[Gyan]

The engine runs like crap. It starts up fine, till it warms up! I've set the needles according to what Bill Meador stated on another post, LOW @1 1/4 & high @1 1/2. This is with the air cleaner on. It runs, but has intermittently misses. I would consider ignition except for 2 things, 1) It has a new RCexel box & 2) it only misses when at operating temp?? I'm using a NGK CM6 with a plug gap of .018" Any ideas? Running rich (cause of air cleaner) Would a new plug be prudent now?
I've been running the G230 PUH & the G260 PUH for years now without any issues, this engine seems to be alot more sensitive.

[Billme]

Gyan,

Definitely change the plug since its easy to do...Was it running good before? or never?.. If its the plug, play with the gap on the new one by increasing the gap a little at a time... ...Hopefully you will find your sweet spot on it...
The fan hitting the pickup would not make it miss..It either works, or it doesn't...I saw this on another thread, and just through that in there..

The 20 is my favorite engine, but mine is not stock, I run the same ignition as you....I seal the head gasket with Honda gasket seal #4, same as yamaha...

[Gyan]

Thanks Bill, Where do you get that Honda gasket seal #4? Would that work sparingly around the carb gaskets I wonder?? I did a crankcase pressure seal & all was good except the carb pump port hole, so I cut a thick paper gasket & it seemed to fix the cold start issues I had. I dont think this engine has ever ran "good" yet. Those carb settings you state are they with the carb filter on or off?

[Billme]

I run a Ma air filter, it has the least differential of all I have ever used...Those settings, or any setting I suggests are always starting points, although they may be close, you must still determine if your motor is running OK...
Since you done a pressure test, that's fine..I have used the sealer on carb gaskets, just use a very thin coat..If you cut your own gaskets thick, you should not need it, unless your material is to hard....

The thing to do on this engine is to run it on a test stand with a prop and break it in, or find problems for someone new to the engine...Once you determine it running good, and you put it in the model, and start having problems, check the fuel system..Do all the easy stuff first.. After that, then its time to look at the drive train...Clutch, and Auto clutch... They work together...
Is it a miss continually, or is it a kinda pop miss every now and then?

[Gyan]

It's kind of a pop miss now & then but quite often. It's not constant for sure. I'm flying up to Whitehorse, in the Yukon for a 4 day contract job this morning so I can't check out your fine suggestions but I will be monitoring my emails...I'll let you know how it goes once I get her up in the air.

[MotorRotor]

Originally Posted by Gyan

The engine runs like crap. It starts up fine, till it warms up! I've set the needles according to what Bill Meador stated on another post, LOW @1 1/4 & high @1 1/2. This is with the air cleaner on. It runs, but has intermittently misses. I would consider ignition except for 2 things, 1) It has a new RCexel box & 2) it only misses when at operating temp?? I'm using a NGK CM6 with a plug gap of .018" Any ideas? Running rich (cause of air cleaner) Would a new plug be prudent now?
I've been running the G230 PUH & the G260 PUH for years now without any issues, this engine seems to be alot more sensitive.

Note, a VERY important piece of info that is missing.....what battery pack are you using to power your EI?

And also note the instant responses you received here compared to your similar query on RR.

[Gyan]

Phil I'm using an 1800 Ma nicad pack combined with an on board generator putting out 5.8v. RR time noted for sure. I thought Bill was on RR more...guess not.

[MotorRotor]

Dennis, you did not say what the voltage is of your 1800 NiCad pack. I would suggest that you check the instructions for your EI unit. If memory serves, I believe my RCexell EI requires a minimum of 6.4 volts to operate correctly, so yours may be the same.. So if you are using a max of 5.8 volts (as per your spec for the generator), that would not be enough to operate the EI properly.

If the EI is not getting the proper voltage input, the erratic running symptoms would be very much like you describe. Therefore no amount of carb tuning would eliminate the problem.

As for going to RR for help on a Century heli. You will find a lot more help here on HF, simply because a certain group of MinAir fanboys on the gasser forum of RR has succeeded over time to get most Century knowledgeable people banned from RR. Most have never bothered to get back onto RR, as they found HeliFreaks to be a much less biased site.

[Gyan]

The voltage in the manual & on the ignition box says 4.8 to 7v & 5.8v is bang in the middle. Should be good, no?

[MotorRotor]

Originally Posted by Gyan

The voltage in the manual & on the ignition box says 4.8 to 7v & 5.8v is bang in the middle. Should be good, no?

It should be alright unless there was a misprint in the manual, or something in the wiring is not letting adequate current into the system or maybe some other reason (e,g, defective EI).

Try bypassing your generator and try a direct battery to ignition and a separate battery to RX system.

[Gyan]

Al at Hanson's reported a crankshaft misalignment. That would account for the vibs i was getting and possible seal leakage as a result. Kudos has to go to the BD3SX, even with a crank out of alignment it was holding the heli stable. Engine gets back on Friday, test flight soon after that.