Starting problems

[bryantma]

Hi,

I'm new to this game, so here is a nice newbie question.

I have 2 new Carson nitro off road cars that refuse to start. They have been starting over the past few days, but due to broken parts they've been off the road (no pun intended) for a couple of days. Now that they are fixed, they won't start.

Part of the problem is that they have built in starter motors and no pull starts. The motors have never been that good at turning the engine over, but now they are rubbish. One revo and they stop. I've taken the glowplug out and they turn over fine. The glowplug has had time to warm and fuel appears to be getting to the carb, but the lack of starting power seems to be the main issue here.

Continued use of the starter obviously wears the batteries down which compounds the problem.

Does anyone have any ideas?

Martin

 

[ImBroken]

As long as you have a good glowplug ignitor, you can loosen the plug a couple of turns and try to start it. This will relieve some of the pressure while trying to get it running. Once running, just tighten the plug back up..
Unfortunately, not too many people here in the states will be familiar with those buggies, but that doesn't mean we can't figure it out..

 

[bryantma]

Thanks for those notes. :bow:

I've tried with different tensions on the glowplugs and they now almost start. A big improvement. I'm going to charge the batteries again and then try once more.

I think that we are in with a fighting chance now. :boxing:

As for not knowing this exact model of car, I'm not worried about that. I'm here to learn the basic principles of these cars now and I'll move on to the specific model variants once I've mastered the basics.

Luckily, I'm a generally technical and logical person. I've already rebuilt one of these cars as the starter motor died and I didn't fancy sending it away for 4 or 5 weeks for repair under warantee. I thus replaced the motor myself.

I've also found a (fairly) local model shop to become friends with.

I'll get there one way or another.

Martin

 

[bryantma]

Still doesn't actually start though. Last time that they were used they started after several attempts. I'm fairly sure that fuel is getting through and they do appear to fire occassionally, but neither car actually starts. Should I squirt a little gogo juice into the carb or will this flood it?

We seem to be so close... and yet so far...



Martin

 

[ohmygahitscoby]

Are your needles set correctly?

 

[bryantma]

I have needles?

I assume that you are referring to my carb settings? They are set as supplied by the manufacturer and I haven't played with them yet.

I thought it best to get some advice before completely messing the settings up.

There are indeed mixture and idle speed settings. I assume that once I'm sure that I have fuel getting in then it's time to play with the mixture?

As I mentioned, nothing except the tension of the glowplug has been changed since it last ran.

Thanks

Martin

 

[hvymetalalchmst]

there should be three needles;
idle (idle)
high speed needle, hsn (mixture setting)
and a low speed needle, lsn (go poke around your carby)

since its not running, I'm guessing its too lean, and everything else you say is fine. if i were you, i would screw in all the screws right in (not too tightly), counting the number of turns, just in case.

then, unscrew the hsn out about 4 turns (not 4 half-turns!), and unscrew the lsn until its about flush with the housing of the needle. idle, dont worry too much. use the trimmer on remote.

read about tuning problems in the 'general forum'. they should give you more info about tuning, they are quite detailed.

ps. what type of batteries run the starter, and what voltage and capacity is it? if you say the batteries are so weak, it may be possible to replace the batteries to give it more power and more juice.

 

[martrix]

Try out a fresh new glow plug and make sure its glowing bright with a fully charged glow plug igniter. Also check to make sure that fuel is getting into the crankcase/piston chamber.

You only need 3 things to fire it up. Air, fuel and spark.

 

[bryantma]

Excellent advice. Thanks guys. Since it's now 1am here now, I'm gonna try these tomorrow.

I think that it probably is a fuel issue, so I'll look there first. I'm probably goning to be busy with it all day tomorrow. I'll keep you posted...

:shuteye:

Martin

 

[hvymetalalchmst]

oh and dont forget have fresh fuel. older than a month and youll be iffy. if its cold up there, you may want a hotter plug.

 

[bryantma]

Right...

The fuel is only a week old and I can only find one screw so far, that's the mixture setting, I think. Its on the carb at the fuel entry point.

If I try it with the glow plug a little loose, I get smoke out of the gap, so I'm gonna assume that I have air, fuel and fire, just obviously not in the right mix. The plugs glow nicely (a bright orange) and the engines do fire now and then so it must be down to settings, I hope.

I'm just gonna keep trying. Good way to learn. Especially as its Sunday and my local source of knowledge is closed...

Breaking news as it happens.

Martin

 

[olds97_lss]

Does your starting device only turn the engine over, like HPI's savage roto-start? Or does it heat the plug and turn the engine over like the traxxas ez-start?

If it heats the plug and turns the engine over, then you can try and disconnect the wire to the plug and use an actual glow heater to heat the plug. Then it won't drain on your starting device as much.

 

[bryantma]

There is a start button on the remote. Press it once and you get an amber light indicating that the glow plug is warming the engine. After 20 seconds it goes green and then you can press the button again to turn the engine over.

I think that my problem is fuel. The book only says to put your finger over the exhaust to pull fuel through if it won't start. There are no priming instructions. I've tried (amongst many other things) pouring fuel into the carb and this causes a much better result. I'll try it again tomorrow when the batteries are charged again. I've been playing with the mixture screws too and found the place where it sounds best. With a good fuel supply, I think that I'll have cracked it. (Fingers crossed.) I'll clean my fuel lines first, too, just to be sure.

Wish me luck...

Martin

 

[hvymetalalchmst]

wow, your thing sure does sound pretty advanced... autostart using a remote. cool.

if you stick your finger over the exhaust, primes the engine by putting pressure into the backpressure pipe, forcing fuel into the carb. alternatively, you could take off the pipe, and blowing into it until the fuel reaches the carb. keep looking for your lsn... it should be there. around the carb barrel.

like olds said, try disconnecting the glowplug and heating it up manually. 20 sec IMO is waay too long. i put it in for 5-10secs cold and for 1-2 when the engines warm. also, does your starter turn it over for a set period of time?

if it does, and is too long, then you may decide to take apart the circuitry of the starter (both tx and rx), and look for orange disc thingies or black/blue cylindrical capicitors. they store energy, and thus alters the length of time the circuit stays closed. if you are confident with tinkering with your rc car, then you can desolder them and replace them with lower capacitant capacitors, thus saving energy, or alternatively, replace your batteries with higher mAh batteries.

(or just disconnect the autostart altogether and do it all manually with a starter box and glow starter)