I have a new RCEXL twin cylinder ignition system that acts really weird. You do the normal start procedure; choke and flip till it runs and stops, then choke off and flip until it starts. But then the engine will only run for 2 to 5 seconds and quit as suddenly as if you turned the switch off. You can immediately flip the prop, and it will do the same thing; run for 2 to 5 seconds and stop. After doing this for anywhere from 6 to 12 times, it usually will finally take off and keep running. Once it has run for a bit, subsequent hot starts are one flip and away it goes. Sometimes the engine acts a little "baulky" during running, but mostly it runs ok after you finally get it going. It is as if the ignition unit has to "warm up" to work properly.

I put another RCEXL ignition box on the engine with no other changes. Same sensor, wiring, battery, carb settings, etc. With this other ignition box, the engine runs perfectly. Cold starts are normal and it keeps running. The engine in general seems to run slightly better with the alternate ignition box.

Please guys, I know the first paragraph could be construed as to indicate a lean low end, but that's not it. When it is doing it's start/stop routine, if you choke it the engine floods. (even with half choke) Richening the low end of the carb does not help either; it still just starts, runs a few seconds, and stops. Besides, it doesn't do this at all with the alternate ignition box, it runs perfectly. It is indeed a fault in the first ignition box.

Anyone run into this before??

Thanks,
AV8TOR

Try running it on a 5 cell pack. Sounds like an ignition with a marginal output. After they run a bit they "warm up" and the current goes up (25-50ma) and they make a bit hotter spark.

Ok, thanks for the tip! I'll give that a try and report back.

AV8TOR

Hey that worked!! Amazing!

I put a Lipoly with a regulator set at 6 volts and it starts and runs perfectly when cold. Now for the "64 dollar question" though. Is it just some electrical components on the wrong side of their tolerance and on 6 volts it will keep running? Or is it something that is sooner or later on it's way to failure???

Thanks Terry,
AV8TOR

av8tor, got one here doing the same although not quite as bad. After the second or third start it will continue to run and just as on yours, with an alternate ignition it will run flawless never dieing. It never misses at higher throttle settings although it will sometimes die on taxi-in just as if you had cut the switch. One flip and it's running again. It's over 2 years old and since it never dies in the air I have just continued to fly it and it never seems to change or get worse. I haven't tried the 5 cell pack as Terry suggested, but that's next. Thanks for the suggestion Terry.

I don't know if I have ever gotten a definitive answer to this question:

The RCEXL ignition is a fully shielded type, so does it or does it not require a resistor plug?

I am running resistor plugs right now. If it doesn't need them, non-resistor plugs should give it a hotter spark. Right?

Think this unit will keep running Terry? (I won't hold whatever you say against you if it doesn't work out, but your judgement would be far better than mine on this issue.)

AV8TOR

I think the small resistor in the cap lead takes place of a resistor spark plug....not sure. I bet the spark would be better witout the resistor...but then there is the RF problem???? Capt,n</p>

The Rcexl ignition for the CM-6 plug is the only one with the resistor in the cap. The other Rcexl ignitions require resistor plugs to fight noise.

The 1/4-32 spark plug ignitions have the resistor in the cap also. I've flown the Rcexl ignition with no resistor without any problem but not on 72 mhz analog radio systems. Do a thorough range test with the antenna pointing in all directions and engine running at all RPMs and see if you get any problems.

The vendor where you purchased the ignition should have no problem exchanging it for you if that was your desire.

Forgot about that little one Jody. It is in the same boat as the CM-6, the plugs are a little too small to have a resistor inside them hense the resistor cap.
Or so I was told once upon a time, but I did stay at a .....

It's easy to forget about the 1/4-32 plugs since very few engines use them. I probably would have missed it also had I not replaced a plug cap on one today.

Well, it's the "hassle factor". I hate having to package something up and send it back unless it is absolutely necessary. Then in my case, that also means a 120 mile round trip to the Post Office or UPS facility to send it off. Then when it returns, I usually have to pay "duty" to get it across the border to here in Mexico where I live. I would much rather just keep it and use it if there is a decent chance of it continuing to work....

AV8TOR

Oh Boy, well we will start with a big IF.
1. IF your ignition is just a bit on the low side then the 6v will be the answer and you will have no problems.
2. IF you ignition has a component that is failing, the 6v is a crutch. You ignition will start the act the same as it did on 4.8v even though you are on 6v. If this the case you will have some warning and should toss the ignition if it starts to give problems on 6v

Ok, thanks Terry. I appreciate your info and judgement.

AV8TOR