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Old 01-01-2009, 02:38 PM   #1
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Default Issue with my Revo TRX 3.3 Engine

So here's my problem, the engine in my revo 3.3 keeps cutting out. I can drive around at quarter throttle all day long with no issues, motor runs like a dream, idles great, temp stays between 175 and 200, but as soon as I try to go with anymore throttle the engine cuts out. And if I apply full throttle it accelerates and then cuts out and then accelerates and then cuts out never reach a speed of more than 20 mph. I've spent over 2 hours running it and changing the settings of the HSN and LSN. Anyone have an suggestions or may have an idea of what the issue might be?
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Old 01-01-2009, 03:06 PM   #2
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either your HSN is too lean, or you have an air leak somewhere. Maybe a split in a fuel line, maybe the carb, maybe even the engine. submerge the engine in soapy water (with something blocking the exhaust and air filter hole) and blow down the fuel tube, watching for bubbles.
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Old 01-01-2009, 05:09 PM   #3
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175-200 degrees at 1/4 throttle is wayyyyyy to hot! You should be maxing out at 250-275 at full throttle.
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Old 01-01-2009, 05:10 PM   #4
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set the carb back to factory specs and go from there.
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Old 01-01-2009, 06:57 PM   #5
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ok if I don't have an air leak in the fuel system, where are the possible places in the motor that I could have a leak? Also could someone please tell me what is the optimum temp to run the motor at, it seems that every one has a different temp. The manual just says not to exceed 270 degrees.
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Old 01-02-2009, 07:01 AM   #6
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Always follow your factory manual! Nobody knows more about Traxxas stuff than Traxxas. 3.3 optimum operating Temps are 240-260 degrees after a few high speed passes. As the manual says do not exceed 275 degrees. This will cause your engine to lose pinch. (It dosent happen after 1 time) The extream heat will severely shorten the lifespan of your engine. You should not be at 175-200 degrees at 1/4 throttle. Turn the high speed needle counterclockwise 1/4 turn and see what u get
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Old 01-02-2009, 08:28 AM   #7
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OK so you guys don't think this could be caused by an air leak some where in the system or motor. You guys believe it is strictly a mixture issue with my HSN. OK then I will go back to factory settings and start from there and I shouldnt make more than a quarter turn adjustment on the HSN at one time. And I should look for an optimum operating temp of between 240 and 260 after I get the HSN adjusted to allow for the motor not to cut out and bog and accelerate a few seconds and then cut out and decelerate. If this doesnt work where should I go from here?
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Old 01-02-2009, 08:33 AM   #8
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Check for an airleak. It is the safest thing you can do. IF you have an airleak your gonna have to seal it up with RTV. If you richen it a 1/4 and that does not work CHECK for an airleak.
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Old 01-02-2009, 12:24 PM   #9
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Pretty good sign of an airleak when you make some pretty big tuning adjustments with little to no results.

Places for leaks - backplate,carb neck and pinch bolt. Be careful with carb pinch bolt, you can tighten these enough to crack the carb body. Also the backplate joint that needs sealing is under the ezstart/PS, not where the oneway is located. Use either a purpose built engine sealer or O2 safe hi temp rtv. Use as little as possible to get a seal.
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Old 01-02-2009, 03:20 PM   #10
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Quote:
Originally Posted by TADitto View Post
OK so you guys don't think this could be caused by an air leak some where in the system or motor. You guys believe it is strictly a mixture issue with my HSN. OK then I will go back to factory settings and start from there and I shouldnt make more than a quarter turn adjustment on the HSN at one time. And I should look for an optimum operating temp of between 240 and 260 after I get the HSN adjusted to allow for the motor not to cut out and bog and accelerate a few seconds and then cut out and decelerate. If this doesnt work where should I go from here?
Nobody said its not an air leak. We said it shouldnt be running so hot. Richen it up, then check for air leaks
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Old 01-02-2009, 03:44 PM   #11
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it needs richened up that is for sure.. the motor should not hardly get up to temp at quarter throttle
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Old 01-02-2009, 06:54 PM   #12
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Quote:
Originally Posted by joe of loath View Post
either your HSN is too lean, or you have an air leak somewhere. Maybe a split in a fuel line, maybe the carb, maybe even the engine. submerge the engine in soapy water (with something blocking the exhaust and air filter hole) and blow down the fuel tube, watching for bubbles.
I personally wouldnt submerge my engine in soapy water LOL. Just my 2 cents
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