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Traxxas 3.3 piston orientation???

Traxxas 3.3 piston orientation???

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Old 06-05-2012, 08:00 PM
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Default Traxxas 3.3 piston orientation???

Hello all,
I just got a very nice slayer off ebay but cant seem to get it to fire.
It seems as though the engine is building pressure and working against the sealed pressurized tank. I looked at the piston orientation...I believe the notch or cutout in the piston skirt is away from the exhaust header opening.
Is this correct?
Also, when I pull the fuel line off the carb and prime the engine, fuel squirts out.
When I reinstall line to the carb, the fuel seems to stall. when I remove my finger from the prime tube, there is back pressure.
Thanks
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Old 06-05-2012, 08:11 PM
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The notch on the piston skit goes towards the back of the engine. If it was in backwards, it would have done broken the piston skirt on the down stroke.

Screw the top-end needle down till it closes. Open it up 4 complete turns. The botton needle needs to be flush with the inner ring of the link. This should get it running but could be a little rich or lean. Remove the air-filter and put a touch of fuel in the carb and try to start.
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Old 06-05-2012, 10:20 PM
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The notch in the piston skirt is facing the front of the motor. That's there as a relive for the crank as the engine rotates. Note also that the oiler hole in the con rod also faces the front of the motor. If you have any other questions feel free to PM me anytime.
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Old 06-06-2012, 05:36 AM
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Originally Posted by Greg B View Post
The notch on the piston skit goes towards the back of the engine. If it was in backwards, it would have done broken the piston skirt on the down stroke.

Screw the top-end needle down till it closes. Open it up 4 complete turns. The botton needle needs to be flush with the inner ring of the link. This should get it running but could be a little rich or lean. Remove the air-filter and put a touch of fuel in the carb and try to start.
This is incorrect. The "notch" (or you can call it the short side of the piston if you like) goes towards the front of the engine. As stated in the post above, the back plate is relieved to clear the piston skirt on the down stroke.

If you install it backwards, the engine might start, but it will barely run....speaking from personal experience during my nitro newbie days.
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Old 06-06-2012, 05:43 AM
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Originally Posted by Graveyard View Post
Hello all,
I just got a very nice slayer off ebay but cant seem to get it to fire.
It seems as though the engine is building pressure and working against the sealed pressurized tank. I looked at the piston orientation...I believe the notch or cutout in the piston skirt is away from the exhaust header opening.
Is this correct?
Also, when I pull the fuel line off the carb and prime the engine, fuel squirts out.
When I reinstall line to the carb, the fuel seems to stall. when I remove my finger from the prime tube, there is back pressure.
Thanks
Sounds like the High Speed inlet is clogged. Since you bought it used, there's no telling when it was run last, or how it was taken care of. Could be that there's just gummed up fuel, or some dirt in the carb.

I'd take the carb apart, and clean everything thoroughly in nitro fuel, or denatured alcohol. Put it back together at factory settings, and try it again.
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Old 06-06-2012, 07:34 AM
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Yes, I agree about the carb. Thats my next step this afternoon.
Thanks everyone!
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Old 06-08-2012, 05:42 AM
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Yup...gummed up carb. Plus it had been sitting for awhile. All better now
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