ifaweb

Hello all, again

Still having trouble with our first car.

Finally managed to get the car running for more than 5 seconds. I am starting it on a brick and as soon as its running the wheels start turning ... fast! If I apply the brake it stalls, if I put it on the floor it stalls, turning the idle screw when it's going doesn't seem to make a lot of difference and is actually quite scary as there is a gear just below the screw. When the brake is applied the gap in the carb is about 1/8th of an inch.

Anybody had this problem if so any idea's on how to cure it.

Carb gap = 1/8 of inch
High needle = 2 and half turns from closed
Low = 1mm from flush (inside) Having it flush seems to make no difference.

Many thanks, again

Jason

walkingcarpet900

i think your clutch is engaging at brake and idle
so when your wheels stop
it stops the flywheel and the piston
causing it 2 idle

could also be someting else

joecarbery

yes it sounds like a classic case of a motor piston going bad,,as it heats up it looses compression and the cant get the fuel it needs..it only takes about 6 seconds to get to a nice heat point,once a nitro motor gets to iys hightest point of heat the damage is done..new sleeve and piston..some cases a new piston is in order...just a educated thought,,been doing nitro for 30 years..i had the similar thing happen to the big block traxxas trucks,,on a hot summer day i ran my truck for 3 tanks of fuel ..even after cooling each run once the heat ran up it was too late..it would start then quit after i gave it some juice..turned oyut to be i lost alot of compression..had to replace sleeve and piston..just a thought..good luck

ifaweb

How do I resolve it if its the clutch?

av8torjim

I disagree with all of the assessments, particularly if this is a new engine. Running it at wide open throttle with it too lean for even a brief time during break in can damage the piston and sleeve, but I suspect you'd have a hard time overheating an engine in 6 seconds at idle.

First, what engine is it? I suspect that you have the idle set too high (1/8 of an inch is a LOT of gap for most carbs). That's why the clutch is engaging. Also, the needles aren't set close enough to keep the engine running at low speed. I would start with setting the idle gap to about 1 mm. Then set the needles per the manufacturer's recommendations. If you can't get it running at the idle setting, use your transmitter to open the throttle part way and try to get it running. If it still won't start, start leaning the HSN in 1/8 of a turn increments until you get it running. You may need to hold the throttle open a little if it won't idle at these settings. It should be sloppy rich at this point and you will probably have to keep the glow ignitor connected. You also might want to try a hotter glow plug for the very rich break-in settings. Once you get it dialed in with a sloppy rich high idle, you can play with the low speed needle a little. I generally don't touch the LSN until I've broken in the engine and am beginning to lean the HSN for optimum performance. Search the forum to the pinch test for setting the LSN. Good luck.

ifaweb

Just a quick point I have just tried it again and this time the wheels didn't turn and nor would they when I revved the car up. I stopped the engine, started it again and this time the wheels turned?????

The engine has already been broken in and it is a .18 cxp.

Thx

Philster

Remove the clutch, and inspect. A normal clutch looks like this:



That is how it rests when it is not spinning (and thus not engaging the clutch bell). When the engine spins above idle, the drive shaft turns more rapidly, and the rotation forces those spring-bound shoes to expand out, thus engaging the clutch bell and any gears associated with the clutch bell.

If you are getting the thing to spin the wheels when it shouldn't, and other times you rev it up and the wheels don't spin, something isn't proper with the clutch (it's inside the clutch bell, which has the small metal gear[s] on it)

av8torjim

I assumed that you were still breaking in the engine because you said it was a new car. If the engine has been broken in and has run properly in the past, I would look first at the clutch, as noted above. If it's not the clutch, look elsewhere in the drivetrain. It's strange that sometimes the wheels spin and other times they don't. What kind of car is it?

ifaweb

The car is an Atomic Warhead which looks identical to the Redcat Tornado BB and Exceed Extreme. It was purchased from a boot sale (basically a sale in a field where people sell all their unwanted stuff from the boot of their car). It has been run for approx 6 months so I'm assuming its broken in.

Thx

ifaweb

I have checked the clutch and it looks like this, not an expert but nothing obvious jumps out at me???









Does it look OK to you?

Thx

jdm_k20

Looks fine to me. I thought it might of been the clutch spring, but it looks intact.

pythonfan

My Feedback: (1)

i see something that will cause ur early engaging, ur shoes are in the wrong holes.


see in the pic, ur setup is in the red, the motor turns clock wise, but in the pic it looks counter clock, but because of that set up the clutch engages much sooner, just move them over a bit to were the green dots are, that way the shoes will be trailing giving u a later engagement, see in this pic urs is set up to leading, and jumps sooner, vs. trailing which doesn't take that jump as fast.

ifaweb

I have made the changes to the clutch like suggested it now looks like this can you confirm it's correct.

Many thanks

pythonfan

My Feedback: (1)

yup its good now, can u take a pic of the with the brakes applied with the air filter off, and then at neutral position, then we can help to see if ur carb is good with the idle.

Anthoop

Yes the shoes are now correct.
Edit-beat me to it pythonfan.

Nick2618

thats 1 point for joe. Noticing the clutch shoes on backwards.

mazdab2600

nice catch joe.[sm=thumbs_up.gif][sm=thumbs_up.gif]
you get the 2 thumbs up.

pythonfan

My Feedback: (1)

lol thanks guys, i also am noticing a few things now i did not see before like this
ok this pic was photoshopped to see it brighter


now this is what I'm noticing


i would suggest getting some wd40, and a air compressor, or if u don't have one get they air key board cleaner at ur local radio shack walmart etc... and clean the motor down real good. the hsn looks like u have a leak, and cause the motor run at a very high idle so u might want ot look in sealing ur motor, this may be done on a big block but it still applies for small blocks
http://www.savage-central.com/module...wtopic&t=54465
and also it looks like ur ideal screw is about to fall out.

ifaweb

Thanks for the advice folks, finally got the car running up and down the street. It's running high idle like you say python, so much that I have to brake to stop it from shooting off. The gap on the carb is only 1mm. I might have a go at the engine sealing once I have got the appropriate sealants. The car still needs tuning slightly but I have it running Ok'ish at the moment and I'm loathed to spoil it.

My next job is to get 2nd gear running as no matter how many revs I give it 2nd doesn't engage I have loosened the screw as suggested but to no avail as yet, I will persevere.

Can I just say thanks to all those that have helped over the last 3 or so days, it is really appreciated by me and my boy.

pythonfan

My Feedback: (1)

no problem man that's what were here for, one thing that might help you is these few vids, again there not for ur car but they will help, and don't say i don't need help, i still watch them to keep my mind fresh on the info cause it applies to the little cars to.

tunning 1
http://www.youtube.com/watch?v=oSmMz...eature=related

tunning 2
http://www.youtube.com/watch?v=BJFsJ...eature=related

2speed adjusting
http://www.youtube.com/watch?v=w5mzva_hu6Q