Engine trouble... need help.... please

[Plaidfish]

I was playin w/ a OS .21 RG today...everything going fine...took a tumble....minor repair......started back up let engine warm up a little sitting on the box....popped the throttle to clear it out put the truck on the ground and hit the throttle it dies instantly....Everything sounds PERFECT until I hit the gas But ONLY when it's on the floor, w/ no load on the tires it opens up and no problems....I checked the drive train for anything binding and it seems free...the engine dies so fast i can't hear if it's rich or lean.....HELP

 

[AC48]

It sounds like it is too rich and is not gotting warm enough before you give it throttle. Maybe try leaning out a little bit and see if that helps. Try to get it up to running temp before you put it on the ground.

Also, how old is the engine? Do you think it could be worn out?

 

[Plaidfish]

I was running for about 30 mins before I took a big bump and I had to put the shock back on the tower.....ran for another lap...truck shut down......I started back up temp is still at 200*.....the engine purrs all day (brand new OS RG I just broke it in this week) it shuts off instantly when I throttle it on the ground...I can't see what would be shutting it down like this and it's pissing me off....I havn't been able to run this truck with this engine at the track at all....runs fine in the fields though.....

 

[parris001]

Is the clutch working right? You say it runs fine until it hits the ground which makes me wonder if the clutch is locked in. Also check for air leaks, maybe a loose fuel line caused by the crash. I've had air leaks cause problems with idle quality.

 

[CorradoPsi]

sounds too rich to me as well. and if you just broke the engine in this week. then what your experiencing is natural. just because your through the initial break-in doesn't mean the engine is done wearing in. that will take about a total of a gallon before the motor is running free and at peak performance. so as you run though this first gallon you will need to gradually lean it out as it continues to wear in. from the trouble you are having, i would start by leaning out the LSN first. and after just starting the engine you will probibly need to clear it out by revving it up to about 1/2-2/3 its operating rpm to clear extra fuel out of it before hitting the ground. i find i need to do this whether the engine is hot or cold, especially since OS's like a slightly rich bottom end.

 

[biggy]

i had the same problem with my new rg..i couldnt even get it to fire when i first tried it..went in 2 hours on lsn and 1 1/2 hours on hsn just to get it to fire..

i have had nothing but tuning issues with this motor but i found a cure.. scrap the 20E carb and put a 20L carb (off of a os .21 vzb) has a midrange needle and thermo coupling for that extra tuning this engine needs..now mine runs like it should..hope this helps

 

[rocknbil]

Is the clutch working right?

^ ^ ^ Votes on this one. If it was working fine before and it happened all of a sudden, a mechanical malfunction is the first place to look. Even just a hung-up bearing can do this.

 

[AC48]

I agree with the clutch thing and biggy's comment. You could try a better carb and see if that helps.

 

[Plaidfish]

Still baffled

OK here's the run down'
First let me say that this engine entire setup is brand new (clutch shoes / springs , Flywheel, bearings pipe header and RG)
New clutch checked it, seems fine no scarring in the endbell bearings are new (kyosho), I used 1.0 spring weight.
it's doing the exact same thing every time.
if I leave the truck up on the stand and pop the throttle it engages the clutch and spins all 4 tires...it sounds beautiful, I let it warm up until the RPMs drop a little, give it a little gas 1/2 - 2/3 throttle to clear it out and it screams (still sounds Awsome). I put it on the ground and it's still sounding great, I give it gas and it dies instantly. I can't even hear if it's dying cause it's too rich or too lean. It sounds like something is binding it instantly like I grabbed the fly wheel w/ a vice and jammed it....but it starts right back up and does it all over again......I don't want to go to LHS and be the butt of the simple repair jokes for the next month. I've replace ALL of the fuel lines just to eliminate the possibility of air leaks...the engine is about a 2 weeks old and I put about a 1.25 gallons through it...
ANYONE have anymore tips....please
I'm bringing it to the LHS tommorow if I can't get this tonite after work...
thanks to all for the input....
love the site / great help

 

[Plaidfish]

Found the problem, had a hairline crack in the endbell..couldn't see it until I pulled on it with some serious muscle..with load on wheels (ground) and engine it pushed it out enough to seize up....don't know how the crack got there though....everbody seemed to think the clutch was the culprit so I kept lookin at the damn thing until I fingered it out....My LHS said this was a new one to them