What would cause multiple plug burnouts?
 

The unit is a AMT-180, fresh from the factory, I got several good starts out of it and last night for some unknown reason, it started burning out plugs. I went through six (6) before I ran out trying to get it to restart. Looking at the manual, it says to adjust the "glow" by lengthening or shortening the lead wire attached to the plug.

Since AMT USA does not have any EDTs to sell, don't ask me about that.

Has anyone else run into this before? I am headed to the hobby shop today to get more plugs so I can diagnose this by this weekend. I would like to maiden my Tam F-16 at that time, that is unless some other type of BS grounds me.

Andy

RE: What would cause multiple plug burnouts?
 

Can you reduce the glow plug power. I had a similar problem on my Rhino, and reducing the power on my glow plug output solved the problem.

RE: What would cause multiple plug burnouts?
 

Rhino's EDT lets you adjust it. I cannot find a way to do the same on the AMT unless someone knows how. I would call AMT but they are too busy to take care of customer service right now.

RE: What would cause multiple plug burnouts?
 

What if you use a weaker battery ?

RE: What would cause multiple plug burnouts?
 

The ECU requires a 11.1 volt battery or it will not run. It then regulates the power to the glow plug.

RE: What would cause multiple plug burnouts?
 

Andy,

Try not pulling so much of the coil out. Also, heat the plug wityh a glow plug ignitor BEFORE pulling out the coils.

Worst case scenario, I'll sell you a Jet Central at a good price!

RE: What would cause multiple plug burnouts?
 

Hi Andy,

You can try annealing the plug before you pull the coils out. Just hook it to a nicad starter for maybe 10-15 seconds, this can help.

Also, I don't know what plug you are using now, but NovaRossis can take a lot of voltage, I would suggest a NovaRossi 9, I run those up to 2.7 volts, they might survive your high voltage ECU.

Hope that helps,

RE: What would cause multiple plug burnouts?
 

If you are just trying to get the engine to light, use a freshly charged nistarter on the plug instead of the plug boot. I started my AMT280SP this way as it did not have an onboard glow from the ECU. I think though that I made my own 2V (2.4) ni starter with a couple rechargable C cell batteries as anything less than a fresh charge on a regualr ni starter wouldn't light it.

RE: What would cause multiple plug burnouts?
 

Good idea except that the ECU registers an error when the plug doesn't get positive contact. This is the semi auto start ECU. Just put air to it and it starts automatically.

RE: What would cause multiple plug burnouts?
 

Thanks Matt, I will try that.

RE: What would cause multiple plug burnouts?
 

Put a plug (hope it lasts) into the circuit that the ECU sees to fool it. Then use another plug with a NiStarter/2-volt dry cell or whatever in the turbine for the real start. Should work fine.

RE: What would cause multiple plug burnouts?
 

Hey, thats a great idea! If all else fails I will try that. There's more than one way to skin a cat!

RE: What would cause multiple plug burnouts?
 

Better you use a car bulb of 12V to fool the ecu, even if it receives full battery voltage it will not be burned out.

Joe

RE: What would cause multiple plug burnouts?
 

Don't forget to ground the uninstalled plug. to complete the circuit.

RE: What would cause multiple plug burnouts?
 

Andy:

I have a low time 1999 AMT Mercury that I had Bennie upgrade to his new auto-airstart V2 ECU.....I use Rossi R-8 plugs exclusively......I haven't mounted it in my ARF Bandit yet, but bench running, about 10 runs so far, plug is still going......I also have an auto-airstart Olympus NL, also only bench run with an R-8 plug and it is still good after about 10-15 bench runs.....I have run my Peggy NL electric autostart for 120+ runs on a plug.....

One of the nice things about the newer ECU's from AMT USA and NL is that you don't have to screw with the external igniter......I would check your plug voltage under load, pull out the coils no more than 1/8", and anneal the plug with a glow driver for 15 secs as previously recommended......Last time I checked, I think my voltage was 2.45......No way for user to change this without talking to factory to open up the ECU, but with my Peggy, I have not had to touch anything, now on my third season with that motor....

It would be nice if you could borrow an EDT to check startup parameters..... if the plug stays on too long after ignition, plug life can be shortened......you can also check that by putting a voltmeter across the plug during startup....it should turn of with 2-3 seconds after light-off and initial temp rise....

Tom

RE: What would cause multiple plug burnouts?
 

After another night of burning out plugs I have determined that the voltage is way to high. The only way to adjust it is with an EDT or the software. Both of which I do not have. I even tried to watch a plug out side of the motor (by hooking it up to the plug wire and grounding it on the engine). The element burns out in a flash on startup.

I have a Netherlands EDT. I will hook that one up. I'm sure it will work but it is full manual start. (not to mention the hassle of taking it out of another jet and installing it in this one. But hey this is JETS right - It's supposed to be fun Right? I'm having a blast.

RE: What would cause multiple plug burnouts?
 

Andy, I can not recall if you stated what plugs you are using. Regular plugs are something like 1.5 volt plugs. The Rossi # 8s are 2.0 volts plugs. Matt said that the NovaRossis are high voltage too. Have you tried any of these higher voltage plugs? Perhaps they will work fine without burning out.

RE: What would cause multiple plug burnouts?
 

Andy,

Try this.....hook up a volt meter to the glow plug adapter and see how much voltage it is sending to the glow plug on start up. This will at least confirm what you think and give you a place to start.

RE: What would cause multiple plug burnouts?
 

Thats probably only going to work for the instant before the plug burns out. Open circuit voltage might be anything depending on how the ECU is designed.

RE: What would cause multiple plug burnouts?
 

I have found that the ECU will actually adjust current, not voltage, in my tests, I found I always had the same voltage with no load (no plug)regardless of the ECU plug setting, the actual final voltage is defined by the load. Why don't just fix the root of the problem? Check to verify if you see any kind of obstructions on the plug hole, possible contact with the combustion chamber, etc. Or have the turbine checked, I still believe the problem is not the ECU, IMHO I don't see you getting anywhere here...

RE: What would cause multiple plug burnouts?
 

I had two rossi plugs that I bought from Dreamworks (for turbines). They both got toasted. I am installing the other ecu tonight. I have run 1.5 volt plugs in turbines before without any problems. I've even started them without pulling the elements out and even with idle bar type plugs. They shouldn't toast in a fraction of a second. Usually if the plug can't handle it, it will start one time and be dead on the next run.

Thanks for all of the replies guys. I think the problem will be resolved with the other ECU I installed tonight. I will deal with the paper wrapped AMT USA ECU later once I get the software to see what voltage it is set at.

RE: What would cause multiple plug burnouts?
 

Please let us know how it turns out.

RE: What would cause multiple plug burnouts?
 

I give up - NO MAS. I installed the other ECU and it wouldnt start. LOW RPM error etc etc. The Tamjets F-16 project is permanently on hold until AMT USA sends me the new replacement 180 they promised me. I'm flying the F-86 this weekend that has a Jet cat in it - which btw has never failed to start.

Andy

RE: What would cause multiple plug burnouts?
 

Hey Andy Did you get my PM?