Help!!!

[laez]

Hey, first post here.
For the life of me I can not firgure out what is wrong with my car. It's a brand new Cen Rally (Fun Factor) with a NT-16 engine and a dual needle carb. I broke the thing in by running fuel through it a number of times plus some slow driving per Cen's instructions. My engine runs inconsistantly. I start it up, let it warm up, and then begin to run it. It will run perfectly for a while, but always after about a fifth of fuel has been used (4/5 remaining in tank) it starts to idle/run erraticly and eventually dies. I have tuned and tuned the needles to no avail following guide after guide. I just set everything back to factory after break in settings (3 turns on high, 1-1/2 turns in from flush on low) and i'm still having the same issues. After the engine dies I have a hard time getting it to run again. The trouble I have is getting it to start taking fuel again. When I press on the primer, or blow on the tube of the exhaust, the fuel does not want to go back up to the carb with out a fight. I have to pump the thing over and over to get it to stay up there, or blow on it for around thirty seconds. It just falls right back down into the fuel tank (I can hear what sounds like an air leak coming from somewhere in the engine). I can cover the exhaust holes and pull on the starter which gets it up there instantly, but when I start it it pulls the fuel out of the line and then shuts off. The fuel system is air tight when I take it apart and try to blow through the exaust pipe while covering the carb pipe. I have clipped the lines and reseated all the connections to ensure they are air tight as well. After pumping it and playing with it I can usually get it to start up and stay running again, but after more fuel is expended it has the same problem. If anyone can help that would be awesome as I have been working on it for days and can't figure the thing out. This thing was not cheap!!!

Thanks so much

 

[aj200415]

sound real lean. How hot is it running?

 

[Bryson]

Sounds real lean. But also you may want to make shure you carb and backplate are sealed correctly with RTV silicon. And as for the dyeing through the tank you can try adding a longer pice of fule line to the exaust to make compersion stronger. That should help if not then it is a air leak.

Bryson

 

[olds97_lss]

Get a temp gun. Put a drop of water on the top of the head when it stalls out on you next time. It should sit there and sizzle a little bit. If it sizzles and jumps off, your way hot and need to richen out your settings. If the drop just sits there and slowly evaporates, your already too rich, but that doesn't sound likely.

The fuel running away from the carb is very indicative of a hot engine. The fuel is boiling at the carb inlet and gets blown back up the line.

 

[laez]

Get a temp gun. Put a drop of water on the top of the head when it stalls out on you next time. It should sit there and sizzle a little bit. If it sizzles and jumps off, your way hot and need to richen out your settings. If the drop just sits there and slowly evaporates, your already too rich, but that doesn't sound likely.

The fuel running away from the carb is very indicative of a hot engine. The fuel is boiling at the carb inlet and gets blown back up the line.

That makes sense. Where am I lean at? the bottom or top? I have tried turning them both up, and i'm getting smoke out of the exhaust... isn't that a good sign?

 

[olds97_lss]

Smoke is a good sign, but there is more to tuning than smoke.

I tune with smoke, sound and temp. If your engine is boiling fuel in the carb, it's not, regardless how much smoke your getting. You might have an airleak in the fuel delivery system. Like a pin-hole in the fuel line, cracked tank, leaky primer (almost always a leak), leaky carb neck or leaky backplate.

 

[laez]

Get a temp gun. Put a drop of water on the top of the head when it stalls out on you next time. It should sit there and sizzle a little bit. If it sizzles and jumps off, your way hot and need to richen out your settings. If the drop just sits there and slowly evaporates, your already too rich, but that doesn't sound likely.

The fuel running away from the carb is very indicative of a hot engine. The fuel is boiling at the carb inlet and gets blown back up the line.

Ok, So I took your suggestions and it looks like It's working out. I took the low needle out 1-1/2 from flush, set the high needle at 3 full turns (I actually started higher but flooded the engine =( ) and cranked her up. After warm up I turned up the high needle up until the RPM when down. Turned the RPM screw up and tweaked around and I was able to get it to run through two tanks without stopping! I let her run out of fuel and she reved up right before she shut down. I put some after run in the engine as well (is that a good idea?). This is my first Nitro! Still have my electrics, but I don't see my self going back if this one works out!

Thanks!

 

[olds97_lss]

ARO is always a good idea when your shutting down for the day. 4 or 5 drops down the carb or glow plug hole (personal preference), then turn the engine over a few times and your good to go.

Whenever you shut the engine down (especially during break-in), put the piston at BDC (bottom dead center, at the bottom of the stroke). This allows the top of the sleeve to contract where it's supposed to, or at least that's the theory.

Get a temp gun. It's a great tuning aid and will help you get a feel for how the engine is performing. After using a temp gun for a while, you will know what too hot sounds like and can use the gun to be certain.

 

[laez]

ARO is always a good idea when your shutting down for the day. 4 or 5 drops down the carb or glow plug hole (personal preference), then turn the engine over a few times and your good to go.

Whenever you shut the engine down (especially during break-in), put the piston at BDC (bottom dead center, at the bottom of the stroke). This allows the top of the sleeve to contract where it's supposed to, or at least that's the theory.

Get a temp gun. It's a great tuning aid and will help you get a feel for how the engine is performing.

Thanks for the suggestion =D

 

[bourney2006]

replace all your fuel line's mate as that may be your prob, or it could be your tank and fuel is covering the hole so when it goes below the whole too much pressure from the tank is escaping