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Old 09-20-2009, 07:57 PM   #1
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Default Brake Stalling Problem - Pls Help



Everyime I hit the brakes on my 1/8 nitro it stalls the engine.

I cant work out whats causing it. I have had a close look at the throttle linkages and when I hit the brakes it doesnt push the carby in any more than when its not on the brakes (if that makes sense).

Ive tried adjusting the linkages, rasiing the idle. It runs fine but hit the brakes and it stalls.

If I very slowly apply brakes you can hear the revs drop.

Any ideas?
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Old 09-20-2009, 08:17 PM   #2
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sounds like a clutch problem.
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Old 09-20-2009, 08:22 PM   #3
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this should be a simple one to fix
First check to make sure that the carb doesnt close all the way when you apply the breaks. if it does adjust the idle screw in untill the carb is cracked ope about 1 mm. it sounds like you did one way to tell is if the idle is properly adjusted the car will remain stationary and idle well without breaks

second insure your idle is not too high. if it is unscrew the idle screw till it is properly adjusted see solution one

third the clutch is most likely the problem if the first two didnot solve it and this will involve some know how and please use your instructions as i can only use past problems to help you. you can do this with the engine in the car but it will be easer to do it out of the car.
1. remove the engine from the car, remember to dis connect the pipe, fuel line, and linkages
2, remove clutch bell and inspect the inside for melted clutch, debris, and damage. CHECK THE CLUTCH BEARINGS, if they are seized or burnt they must be replaced!!! if the clutch bell is damaged replace, if not use light sandpaper, emery cloth, or steel wool to remove melted clutch particals. untill the inside is clean and looks new.
3. inspect the clutch, check for extreame wear, broken shoes, broken springs. if nothing is broken apon removal check for debris that held the clutch open. if not clean the springs with break or electric motor cleaner. next clean the shoes, by using the sand paper or emery paper ot bring the face of the clutch back to a like new appearance and also dont forget the moving surface for burrs, if so remove with sand paper.
4. place shoes back on fly wheel and check for free movement. if you are good to go replace all things you took apart in reverse order.
also besure to take note of shim placement and gear mesh on setup.
hope this helps and let me know
chris
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Old 09-20-2009, 08:22 PM   #4
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sounds like your idle gap isn't set properly. it sounds as if your radio is set to keep your idle open, but when you mash the breaks, it closes too far. best way to check if this is the problem, do the following.

start your engine with your car off, and use your hand to pull the throttle open and close. push it closed all the way, and if it dies, then your idle gap isn't set correctly.
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Old 09-20-2009, 08:27 PM   #5
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Quote:
Originally Posted by poncec23 View Post
this should be a simple one to fix
First check to make sure that the carb doesnt close all the way when you apply the breaks. if it does adjust the idle screw in untill the carb is cracked ope about 1 mm. it sounds like you did one way to tell is if the idle is properly adjusted the car will remain stationary and idle well without breaks

second insure your idle is not too high. if it is unscrew the idle screw till it is properly adjusted see solution one

third the clutch is most likely the problem if the first two didnot solve it and this will involve some know how and please use your instructions as i can only use past problems to help you. you can do this with the engine in the car but it will be easer to do it out of the car.
1. remove the engine from the car, remember to dis connect the pipe, fuel line, and linkages
2, remove clutch bell and inspect the inside for melted clutch, debris, and damage. CHECK THE CLUTCH BEARINGS, if they are seized or burnt they must be replaced!!! if the clutch bell is damaged replace, if not use light sandpaper, emery cloth, or steel wool to remove melted clutch particals. untill the inside is clean and looks new.
3. inspect the clutch, check for extreame wear, broken shoes, broken springs. if nothing is broken apon removal check for debris that held the clutch open. if not clean the springs with break or electric motor cleaner. next clean the shoes, by using the sand paper or emery paper ot bring the face of the clutch back to a like new appearance and also dont forget the moving surface for burrs, if so remove with sand paper.
4. place shoes back on fly wheel and check for free movement. if you are good to go replace all things you took apart in reverse order.
also besure to take note of shim placement and gear mesh on setup.
hope this helps and let me know
chris

Well said.
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Old 09-20-2009, 08:43 PM   #6
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I had the same thing happen today.
I found two broken 1.1mm clutch springs
to be the problem. One of the broken clutch
springs had flipped around and jammed the
other clutch shoe against the clutch bell.
I have had a clutch shoe spring break before,
but never two outta three.

Last edited by rageworks; 09-20-2009 at 09:02 PM.
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Old 09-20-2009, 09:20 PM   #7
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Funny you should mention the clutch. I just had a new one put in this weekend. Local shop couldnt get the metal one like what was in it so they put a plastic one in. Its been doing it since then. (Dont know why this hasnt occured to me before).

Ill pull out the clutch tonight and have a look. I have not tried moving it by hand when idling, I will try that tonight. Ive tried to trim it, changed the linkages, changed idle, havent really touched the tune much but its on the rich side.
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Old 09-21-2009, 03:09 AM   #8
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yeah what powers said. sounds like a hung clutch. had a ear come off a clutch about a month ago and we tried for two hours tuneing and retuning until a friend walk up and says "check your clutch". 20 mins later i was in the qualifier racing for glory
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Old 09-21-2009, 05:51 PM   #9
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Didnt get a chance to pull it out last night. Will do tonight.

Would the material the clutch is made out of make a difference? The one I removed was metal and the one I put in was plastic (only one available)?
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Old 09-22-2009, 04:28 AM   #10
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Not really unless one of the carbon shoes have broken. I'm guessing either a seezed bearing in the clutchbell or a broken spring.
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Old 09-22-2009, 05:01 PM   #11
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Damn I didnt think about the bearings, hope its not them LOL.

Everytime I take this thing out it breaks something. Thats what I get for buying a cheapo though LOL.
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Old 09-22-2009, 05:04 PM   #12
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Make sure your brake epa on the transmitter is set correctly also.
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Old 09-22-2009, 05:41 PM   #13
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Originally posted on the RC8 thread:

"Funny you should ask....mounted my favorite Ofna flywheel and clutch...

Motor dies at every brake application...we tear it apart...put it together...tear it apart...put it on the ground...runs great until the brake kills it...tear it apart...aww, c'mon...we've got some hot buggy wheels tryin' to figure this out...how hard can it be???

Turns out the rear brake disc would contact the face of the flywheel when the brakes were applied...I could see it was close...so on the last of many dis assemblies I see the faintest black rub on the face of the flywheel...

As goofy as we are we were high fiving one another 'cause this was a tough one...LOL"
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Old 09-22-2009, 09:39 PM   #14
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Thanks for the info but I dont think my rear brake disc is anywhere near the flywheel. I took out the clutch last night, other than a little wear it looks fine so its got me stumped.

Might check out the bearings tonight.
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Old 09-23-2009, 06:43 PM   #15
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Me experience with bad clutch bearings is that the engine will start and just die as soon as you pull the throttle and the clutch tries to engage. Have you checked your fuel tank for cracks or make sure the spring on the lid is closing properly. How much fuel is in the vehicle with this happening? Is the clunker in the fuel tank still near the back of the tank?
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