Carb problem

[chuckmando]

I have been having poblems with my Hyper7 since I broke it in. Dirt might have gotten into the carb. I cleaned it out and tried all different setting, but to no avail. It starts amost every time on 1 or 2 pulls. But I cannot give it more than 1/2 throttle. Question, how can I tell if either of the needles are bad? Thanks

 

[SkyMaxx]

You can remove them from their fittings and visually inspect for damage. You might also try to return the needles to the factory presets and go from there.

When you give it half throttle, it dies? This to me sounds like it is running too lean (fuel starvation). If it bogs down then dies when you lay on the throttle, it is probably running to rich (basically flooding the running engine). Either way, I'd first try the factory presets for that engine (ask El Pirata, I believe he has a .21 Hyper in his T-Maxx). Then retune. If you still have the probelm, remove and inspect the needles.

 

[chuckmando]

Thanks SkyMax,
When the carb was apart, the side does not move in and out freely. I sprayed it and used afterrun oil. Is only a little better, but noticed the slde rotates. I never took off the accordian. Not sure what to look for.

 

[chuckmando]

I replaced the carb with a friend's. Works alot better, but not pefect yet. It's raining here, so that can be contributing to it. I'll see when it stops

 

[SkyMaxx]

The high humidity of the current rainy weather will mess with the performance of your engine. These little air breathers don't handle moisture so well.

When you say side, are you meaning "slide"? As in do you have a slide carb?

If it is a slide carb and it is showing the ability to rotate, that is a bad sign. That indicates that the idle set screw, which is supposed to go tongue in groove into a track on the barrel of the slide carb, may not be properly seated. The HSN might also be in the damaged category as it also has a point that rides the barrel. I am not quite familiar with how the LSN interacts with the carb on a slide carb, but I would imagine that it is probably fine. The needle that usually gets all the abuse is the HSN.

Glad you found a bud to loan you a carb. Hopefully, you will be running right as rain as soon as the rain goes away. Let us know if there is more we can help with.

And as much as it pains me to say this, I agree with Matts. Depending on how much dirt you think went into the carb, if any made it past the carb and into the engine casing...you may find bigger problems. A single grain of sand can completely destroy the performance of these little buggers. You may want to remove the head and give the internals of the engine a real good once over. Look for big nicks, gouges and or scrathes. The areas that are of most concern are not necessarily the head of the piston, but the edges of the piston and the sleeve. The scratches, nicks, or gouges can cause a bad seal and a loss of compression. This means that the fuel and combustion gases can leak around the piston during its stroke. This will give you a distinct loss of power from the engine.

 

[chuckmando]

Thanks for all the replies. Yes it is a slide carb. My keyboard is shot even worse than my buggie (lol). Next on my list to get is a new PC. I had taken the heat sink off prior, and didn't notice any scratches on the top of the head, nor from the side through the exhaust opening. l have never taken out a piston and sleeve yet. I think I may have printed something on how to do it a while ago. I will look for it. I seem to remember I need a special tool. Is this true? My son want to run the buggie in the snow. First things first, must get it running nomally before th snow comes.

 

[chuckmando]

Ok, finally got some good news. After I swaped out the carb for an old used one, the buggie ran for 2 tanks without stopping till I blew out my front servo from a weak hit. I had loosened te servo saver, but I guess not enough. At least I can run this weekend after a new servo of course.

 

[SkyMaxx]

Glad to hear that the problem is solved. The servo will probably be the first in a long and growing list of broken bits and pieces. Welcome to the world of offroad RC. Start stocking up on spare parts...

 

[SkyMaxx]

Sorry to disagree with you Matts. All HiTec servos are not digital. They have a separate line of digital servos. They produce more torque and re-center a little better. The hs-645mg that you mentioned is just one of their run of the mill hi-torque servos. The digital version of that servo is the hs-5645mg.

 

[chuckmando]

SERVO

As a matter of fact, last night I picked up a Hitec 645. I put it in late last night. I hear the servo straining after I let go of the steering if its ond the ground. But not when I hold the car in the air. I had used the rubber pieces on the ends. Maybe it's too high. I will take them off tonight and see if that helps. I also loosened up the servo saver. I think it was way too tight.
Thanks

 

[SkyMaxx]

If you have any trim input on the servo or you bump the wheels out of the straight ahead position, the servo is going to try and return to center or a neutral position. The straining you heard was probably the servo trying to pull the wheels to the servo's neutral position. It is not a bad problem. It just requires you to set the servo properly and get your trim where you want it for wheels straight. The other thing is that new servos take a little time to break in. They will "strain" a little for a few runs as they get used to being used for pulling a load. Set your trim and run the buggy for a few tank fulls. Give the buggy a snake of a work out (lots of turns and esses...from one extreme to the next) and make sure there is plenty of opportunity for the servo to re-center itself. The strain will go away.

 

[chuckmando]

Thanks, I had the buggie in hand ready to go out and the rain came. Just enough for me not to go out. Looks like Sat is the day.

 

[chuckmando]

Finally

Ran for a couple of hrs today. The only mishap was the wing snaped off on a flip. At least we boke something other than the pull start or the carb. We geared to 16T pinon and the hyper handled it well. I was a little suprised the top end was pretty good for a motor that costs less than my .12.

 

[SkyMaxx]

The price tag on the engine is not always a performance indicator. An intelligent person who knows what to do in the way of tuning an engine and then properly gearing for performance, can make just about any engine a performer.

Glad to hear that things are working well for you.