Revo63

Tuning ?. Been out of nitro for a while so this prob sounds dumb but. I have a Revo put a Picco 21 in it starts fine but I have to ease into it to get it going otherwise it will die out Also when I am up and running if I hit the throttle hard it dies out on me. Suggestions?

JoeMaxx

Does this happen after the engine is hot?  We will explore this after you test the glow plug.

First thing I would do in this case is replace the Glow Plug.   Pull it out and inspect it to see if it is glowing bright orange or yellow hot.   If it is red in color it needs to be replaced and starting to fail.

Foxy

If it idles and runs mostly OK, I doubt there's an issue with the glow plug, though there might be. I'd be inclined to suggest that the motor is probably running too rich on the low end. Try turning the low speed needle IN a 1/4 turn. If that makes it worse, go the other way, a half turn OUT. If that still doesn't make any difference, return the needle back to where it was and move over to the high speed needle. Try turning it IN 1/8th of a turn. If it makes it worse, turn it OUT a 1/4 turn. Using this procedure you will at least be able to determine which direction is making things better. If turning the needles out is making it better, then you were too lean and richening the mix (anti-clockwise) will make it work better. If turning them in makes it better, then you were too lean. Don't be tempted to make big adjustments of the needles, the low speed 1/4 turn at a time, the high speed only 1/8th of a turn at a time.

JoeMaxx

There is a test for the LSN which us older nitro guys use to adjust this setting. make sure the engine is up to full operating temps to perform this.

Pinch the fuel line it should run between 2 to 4 seconds. 2 Seconds is on the lean side and 4 seconds is on the rich side.I Count 1001 1002 1003 slowly after pinching the fuel lines.

To adjust idle I like to engage the clutch than slowly lower my idle off the ground until the wheels do not spin.

It takes time to properly tune a nitro.

Revo63

K tnx for the info guys when i get a chance ill try the low speed 1st then the high

JoeMaxx

Yes always adjust your Idle first then the low speed needle second before you tune in your High Speed Needle. You may need to readjust your idle again after tuning in your LSNSetting if it is way off.

Onceyou get the low end set it rarely needs readjustment unless you start to have a problem again.

The High Speed Needle requires almost daily adjustments each time you run and I generally spend the first half tank of fuel tuning it in each time I go out to play.

vxlsteve

Turn hi speed needle counter clockwise 1/4 turn it needs fuel to go faster...hope it helps

RC Blogger

Never, ever, adjust the idle speed first.
The low speed needle will make the idle fluctuate as you are adjusting it.
You should start with a slight high idle warm the eng to operating temps then start with high end needle, do some speed passes to adjust the high end first, after thats done start to tune the low end needle, at this point you will see the idle change, if it gets to high turn down the idle speed needle a little. The pinch test should done at about an inch from the carb and it should increase the idle speed and die out in about 4/5 seconds, if its closer to 5 you are a bit rich, turn in the low idle needle 1/16 of a turn. Now that all that is set up you can adjust the eng idle.. Remember, always tune with a warm eng. And always set the eng idle speed so you have about a 1mm gap at the carb slide. Adjusting with less gap will give you a starting problem, 1.5mm or more of a gap will give you too high of an idle and a premature clutch engagement.