Kyosho GS-21R running always rich, for only 10 seconds. HELP

[spens0r]

Hello everyone,
I own 6 nitro RC cars. This is the first one that simply will not cooperate with me. It is a buddy's, and we cleaned the entire thing, and reassembled the engine (twice now...) and when it starts (factory carb settings), it just runs rich for about 10 seconds (lots of sputtering), and then eventually just dies. It has done this for about 100 different combinations of settings of the LSN and HSN (the idle screw is fine). I even took apart the carb and cleaned it. It looks brand new but it will not run for longer than 10 seconds. We posted a video of it on youtube. This is the link below.

Please let us know what step to take next. It gets great compression, the glow plug is brand new, factory and all settings won't work. 10 seconds of run time 90% of the time. Always sputtering fuel. Help please.

 

[MotoGod]

Too rich. Is this engine broken in? If so...lean the LSN a few hours....and lean the HSN a few hours and try again. If it won't stay running, do it again. Factory settings are generally WAY rich, and the engine will barely run if it's already broken in. I wouldn't go too much past half a turn on either up front....if you get to half a turn, start leaning the LSN an hour at a time until she stays running. Then the car should stay idling.

Give it a whirl....it's definitely a tuning issue ;-)

 

[Scrogg]

Or a clutch issue.... I've never heard anything good about Kyosho RTR engines.
Edit; Check the pipe, make sure it is not blocked anywhere or leaking.

 

[Mickstix]

Yup.. Mega rich..

 

[jomofro39]

Hey, this is the guy who posted this, but this is MY account, and spens0r is my buddy whose car this is. We tried leaning it out to the point where we had a HSN setting of 1 turn from closed, and the LSN was also close to fully closed, and it still ran like this, we can't get it to run for a long time, and it will run sometimes for about 3 minutes when we keep the carb open from anywhere from 1/2 to full throttle, and it doesn't even get very high rpm, and we can SEE fuel sputtering into the carb (running without air filter simply to observe), and it is just NOT cooperating. I am beginning to suspect that this is not a tuning issue at all, and something is wrong with the carb. We are not sure where to go from here, as we did take apart the entire carb, cleaned everything, and everything appeared normal. does the issue we are having sound like it could at ALL be the carb's fault, before I tell my buddy to get a new carb? Since it is about 50 bucks (yikes!), he was thinking of just saving for a new engine this summer when he gets back from school, but I feel bad for him being out of his RC (wouldn't you be sad?). Any help is greatly appreciated, thank you in advance.

 

[olds97_lss]

How much fuel has been through this engine? Has it been properly broken in?

If so, set the needles 1/4 turn lean from factory settings and fire it up. Try to run it a bit until it dies (if it will run at all). Check the needles to see if they moved on you while it was running.

I've had three engines so far do that to me after they sat a while (like over winter). The o-rings dried out and allowed the needle to either vibrate completely in or completely out. Usually happens within 30 seconds of starting it.

I felt like a dolt when I figured it out myself the first time. That first engine was a tried and true OS 21RG. One of the most stable tuning/idling engines ever built. On an average day, it would sit and idle cleanly through an entire tank of fuel if you let it and would barely load up at all when you went to accelerate. When it started acting up, the needle was screwing itself in and shutting off fuel. A few $ for new o-rings (HSN and LSN) and it was just fine.