I recently purchased a new CRRC 50cc engine and I can't get this thing to start no matter what I try. I have been flipping that prop for two days now and I think I am about to just give up. I have tried everything I have read on these forums and nothing has worked so far.

I know it is getting a spark because I removed the plug from the engine, hooked it up to the wire and checked it. I have tried all of the priming methods I have read about. I have tried using just the choke and I have tried putting my thumb over the carb and spinning the engine until a little bit of fuel runs out. I also checked the needles and they are set according to the "manual"(which is nothing more then a few pages of safety instructions).

The only thing it will do is backfire. It has probably backfired about 15 times in the past two days and then the prop spins off and I have to start all over again. What should I try next? I have a sledgehammer standing by.

Bad ignition.

Milton

Have you tried using a starter? Normally when you have a engine that backfires it's to rich.

Is it a RCxell ignition or one with silver box.

Milton

???

It is the "silver box". It claims to be an auto-advance unit.

The reason I asked is about 10 months ago I got a 45 and 26 to test and they had the silver box ignition and both of them failed on the test bench( things might have changed sense then) I had to install RCxel ignitions to get them to run.

Do you fly with anyone that might have a spare ignition that you could try out. Dont know if the north and south on the magnet will be right though.

Milton

Did you buy it from a dealer in the US

Milton

Yes, I did buy it from a U.S. dealer. I just haven't contacted him yet because I want to make sure I'm not doing something wrong. We all know how long it can take to send something back for repair.

Could the ignition be faulty and still produce a spark?

Yes - it is possible

It is also possible that your ignition timing is wrong.

yes, I have seen it happen more than once, The first 100 I got would run for about 2 sec then backfire and quiet.

It was a twin and I only had the one twin ignition so I took a single ignition and put it on one cylinder that that one cylinder ran fine, so I made a y harness and used to single cylinder ignitions to test run the engine with no problems

Milton

My last ignition problem was a low voltage battery (1 cell Lipo). It sparked every time but must have been a weak spark because when I put a 4 cell in there it ran like a champ.

Its either ignition timing,box,or battery.Check to see if the plug is firing at 28BTDC.Check battery voltage.If ya dont know how to check timing go to ch-ignitions and look at instructions.While your there see how much his or rcexls are in case yours is bad.What i would do first is call the dealer and ask him to send ya a new box if your timings fine and tell him youll send your old one back.

If it's puffing at you, then the timing is retarded, I have spend endless hours with these engines to get them to run right, and I have found that even when you replace the Ignition with an RCexl unit, the timing will have to be advanced to get it to start and idle correctly.

My experience amongst others, included a very bad sealing of the piston ring (wavy ring not bearing properly), resulting in very low compression. This too makes an engine very hard to start, even with a good ignition.

I am still working on trying to get this engine to start. I tried replacing the battery and that made no difference so I assume the only two things it could be are the timing or the box. I decided to go ahead and try to check the timing. I have been reading up on that but I'm still not exactly sure how to check it or how I would change it even if it is wrong.

When I was looking at it I did notice something that seemes a bit strange to me. When I set the piston to TDC the magnet is quite a ways past the pickup. I don't claim to know a whole lot about engines but it seems that the plug would be firing pretty early.

Here is a picture of what I am talking about. In the picture the piston is at TDC. Is that the way it is supposed to be?

The timing is set at 28-30 deg before top dead center and the ignition retards it to around 3-5 deg before top dead center, The picture looks to be about right.

Could be off a couple deg but the engine still should start.

Milton

Question, when you first opened the box did it have a gas smell like it had been run at the factory, If so the only thing that is different than when they run it is the ignition, Most of the time they use one ignition to test run all engines and then put a new one in with the engine when boxed.

Milton

If I understand what you are saying that means that the plug should fire after the magnet passes the sensor. When I hook up the plug and spin the prop around the plug is firing exactly when the sensor is passed and not after.

Another strange thing I noticed is that if I spin the prop around counter-clockwise it fires right at the sensor but if I just keep spinning it a little farther and then stop and spin it back clockwise the plug will fire before it gets back around to the magnet.

Yes, the engine did smell like gas when I opened the box.

When you flip the engine to start the ignitions does different that when you turn it slow, There is a chip in the ignition that retards the timing about 25 deg and as the engine turns faster up to around half throttle the will advance the 25 deg.

Milton

Have you called or Emailed who ever you got the engine from, If you tell them what it is doing and they think it might be the ignition they might just send you one.

Milton

Here is a picture of a Area 51cc at top dead center with RCexl ignition runs great.

Milton

I have been takling with the guy I bought it from but he wants me to send the whole engine back. It's a lot of work to take it out the plane, etc. That's why I was hoping to avoid that but it sounds like I don't have a choice.


Thanks for all your help.

Hi!
It's very common that you have to choke the engine real good (several minutes ) the first time you are about to start any gas engine.
Check that you get fuel to the carb!

That is really the best thing to do.

Milton