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  1. #1
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    Dangers of Rich fuel mixture in 2.5 trx motors?

    i was just wondering if theres any hazards to using a too rich fuel mixture in the 2.5 motors?

  2. #2
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    Foul plugs
    Carbon buildup
    Poor performance

    Thats about all I can think of. However I'd rather run too rich then too lean. Its alot cheaper replacing plugs and hosing off carbon buildup then it is replacing engines
    Don't drive like my brother!

  3. #3
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    too rich

    I've had a lot of trouble with my 2.5 (I'm sending it to Traxxas this week). One of those problems was the one-way bearing slipping on the starter shaft. I'd have to tear it apart and clean it after every couple of starts. Traxxas wouldn't send a new bearing so I bought one - worked for a few tanks then started slipping again. This time Traxxas was willling to send a new starter shaft - it still slipps but not as bad. Anyway, when Taxxas decided to send the new shaft they asked if I run the engine rich - I told them that I do run on the rich side because I want the engine to last. I was told that running rich wouldn't prolong the life of the 2.5 because it was designed to be a hi-performance engine and would run better and last just as long if it's run at peak performance (I'm not saying the person I spoke to was "right" or "wrong" - I am just saying that's what I was told). I was also told that running rich was encouraging fuel to leak through the back plate causing the bearing to slip.

  4. #4
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    My bearing slips some times. I guess I dont run THAT rich. I just keep a nice steady smoke trail out the exhuast at idle and high speed runs. I do notice oil leaks down onto the shaft and bearing cuasing it to slip sometimes. I havent had much of a problem with it since it will only slip once or twice and then work.

    I run rich to control temps not really to prolong life. Having no temp guage I'm just trying to be on the safe side. I belive who you talked to is correct; to a point. Of course running it too lean is bad. A well tuned engine will burn cleaner and efficiantly (for a 2 stroke! lol) and it SHOULD last you just as long as one tuned rich. There are sooooo many factors when it comes to combustion engine life. Just do what you think is best and hope it doesnt blow up =)
    Don't drive like my brother!

  5. #5
    RC Qualifier ZipTie's Avatar
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    Re: Dangers of Rich fuel mixture in 2.5 trx motors?

    Originally posted by Timdawg54267
    i was just wondering if theres any hazards to using a too rich fuel mixture in the 2.5 motors?
    If it's running so rich that the engine never gets up to a respectable operating temperature then the expansion of the brass sleeve will not work as designed. This would increase the rate of wear on the sleeve.

    The 'pinch' is not there for compression in the usual sense; it is there because the top part of the engine will get hottest and will expand. So an ABC engine is tight at the top when cold and will be closer to straight-sided at operating temps.

    This is one reason there is a minimum temp for break-in.
    "We don't see things as they are, we see things as we are." Anais Nin

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