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Old 05-27-2010, 06:11 AM   #1
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Default Engine revving with throttle closed?!?!

Hi all

Now, I'm relatively inexperienced (as you can probably gather by my begging for answers) so try not to be too impatient with me if I'm making stupid mistakes

I've been running a Go .28 engine on my truggy for a while now, it's been easy to tune, loads of power and has always run great......until yesterday. All of a sudden the engine seems to have gone crazy, it starts easily enough, and will happily sit at idle with no problems, but as soon as i touch the throttle it goes wild, revving up to max revs in a couple of seconds, and staying there till I hit the brake.

Just to clarify, I'm NOT opening the throttle wide, but the car IS revving hard. I've tried running it indoors with the air filter off for a few seconds, and the throttle is staying in the idle position the whole time the engine revs up.

I've swapped the fuel lines, and checked the tank, both seem to be fine. Also the servos are set perfectly. The only thing that has been changed on the truggy, prior to the problems occuring, is the exhaust/engine gasket/seal. It had torn and was spitting a little fuel out of the back, so I replaced it with a new one.

Any ideas, please? I'm stumped

Thanks massively in advance

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Old 05-27-2010, 06:15 AM   #2
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Thumbs up If your engine is revving up....

If you are still revving after what you have done.... you have an air leak.
Carb, back plate or front bearing.
Time for some maint.

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Old 05-27-2010, 06:27 AM   #3
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Can it just develop an air leak as quickly as that? It was running fine in the morning, about an hour (and a seal-swap) later and it would just rev like a crazy thing.

Is it gonna be easier for me to just bin it and grab a new engine? I don't know much at all about maintanance on these things.

Thanks muchly

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Old 05-27-2010, 06:29 AM   #4
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An airleak means that air is accessing the engine at wrong places. (Through the front or back of the engine (engine bearings) or between the carb.)

You will have to seal the engine. A guy named Squirrel on YouTube has a how-to video on this subject. http://www.youtube.com/watch?v=6xwDy-I0Z4I

Take a note on that you need gasket material (used for sealing with). He recommends using gasket material that can withstand enough heat just in case. With this gasket material you can seal the backplate and the carb of the engine. Next up is the Team Associated's Green Slime which he mentions also in the video. Use that to seal the Low Speed Needle (LSN) and the High Speed Needle (HSN), he shows you also how to do that.

Good luck!
Losi LST, Mach 427, JR servos
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Old 05-27-2010, 09:32 AM   #5
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Originally Posted by tex1 View Post
If you are still revving after what you have done.... you have an air leak.
Carb, back plate or front bearing.
Time for some maint.

Sponsors: Xray, RC America, Novarossi, Indy RC World Paint by RJ, Vp Racing Fuels, SPD Mods, Avid Bearings, Desoto Racing, Speed monkey Batteries
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