Engine keeps failing. Can anyone help?

[CaptainMTM]

Hi everyone,

I'm new to the forum and new to the RC world so please bare with me if my question is silly or not correctly technically explained but I'm hoping some of you can give me advice as I'm growing increasingly discouraged with a problem I'm having.

I recently purchased a new off-road 1/8 scale Nitro Buggy in RTR condition. Not sure of the name/model but it looks nearly identical to this one:

http://image.ec21.com/image/amax07/...ale_Lightweight_Version_Nitro_Buggy-MONZA.jpg

I visited a local hobby shop and got all the things I would need to run it including fuel, ignitor, batteries, wrenches, screwdrivers, spare glow plugs, etc. Before starting it I closely studied youtube videos and read all the instructions on how to start these cars and thought I did everything right but somehow have been having problems with engine.

I must have tried to start the engine a total of 100 times to the point where my hands are literally soar. On more than half of the attempts the engine just won't start at all. When half throttle is applied it starts for a second but will soon after shut off. It's almost as if the engine stays on for a second or two when the pull (pulley rope) component is pulled out but as soon as I release it or stop applying throttle the engine will just immediately shut off. I'm at the stage where I'm trying to break-in the engine so I've been told to let it idle at least a tank of nitro before running the car at all but it seems like I can't do that at all because in order for the engine to stay active throttle needs to be applied. I primed the engine and made sure all the components are in place and even removed the glow plug and pulled the pulley to release anything if flooded but still that didn't fix the problem. Now I'm stuck and have no idea what to do and the instructions from china are not much help at all. Can someone please help me out? I'm dying to run this car before we get hit with snow here but I just don't know what could be wrong.

Thanks in advance for any help! Cheers

 

[olds97_lss]

Not sure what that buggy is... but regardless, a lot of times, engines show up far too rich to run and with the idle screw not set right.

Pull off the air filter and check your idle gap. New engines that are relatively rich generally won't just sit and idle on their own. I don't let mine idle for a tank, it's too hard on them IMO. I gently run them in decent sized figure 8's with my finger almost always on the throttle keeping it from stalling.

If you can keep it running by giving it gas, then just give it gas and try to get it moving, then keep it moving. But your carb is probably overly rich, so a little leaning of the needles should help keep it running.

 

[Scrogg]

X2 to the above. Preheat the engine before starting it. It does wonders.
A hair dryer willl do just fine. Point it at both sides of the engine block for 4-5 mminutes. Then start it.

 

[CaptainMTM]

Thanks a lot guys.

I'll definately check the idle screw again and see if I can lean it out a bit although I have tried to adjust this screw slightly and have found that I get the highest starting success ratio when the car is on factory setting for this. Good to hear though that I can gently run the car to break it in. I thought I may ruin it or something unless I idle a few tanks first. It's so strange because had I followed the instructions that came with it to a tee it says to let 3-4 tanks idle before applying any throttle.

I'll also try heating the engine tomorrow before firing it up. The car has been in an outside shed and outside temperatures I was trying to start it at on both occasions were around 7 deg so hopefully heat will help.

 

[olds97_lss]

7F or 7C? Either way... that's pretty cool to be starting a new engine. You really should heat the engine up to at least 90-100F prior to starting and I bet it will fire up much easier.

You should wrap the head with tin-foil as well to help it retain heat as you run it. Usually when the ambient temps are below 32F or 0C, I wrap the head and it makes running them much more stable. It keeps the temps up a bit more than without by keeping air from flowing through. When it's that cool out, these things will change in temps very fast and that in itself is generally hard on the engine.

 

[CaptainMTM]

7F or 7C? Either way... that's pretty cool to be starting a new engine. You really should heat the engine up to at least 90-100F prior to starting and I bet it will fire up much easier.

You should wrap the head with tin-foil as well to help it retain heat as you run it. Usually when the ambient temps are below 32F or 0C, I wrap the head and it makes running them much more stable. It keeps the temps up a bit more than without by keeping air from flowing through. When it's that cool out, these things will change in temps very fast and that in itself is generally hard on the engine.

7deg C. I think you guys are right about the heat though because I remember it was a pain to start the car for so long but after a few short starts I actually felt the engine and exhaust get hotter. This is the stage at which my start-ups were most successful. I can't wait to get the thing moving though. After getting a small feel for that buggy from the 30metres worth of circles I did with it late in the evening yesterday I devoted the whole day today to just running it and was so frustrated that after 3 hours I couldn't get it to move more than 2metres on its own before dying. Hopefully tomorrow will bring better fortune with these tips so thanks.