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High EGT Cause?

in 2 Stroke Technical Questions 12 years ago
A friend of mine has an older Rotax 503 that is experiencing high EGT readings. The engine is properly loaded by the prop, the engine timing is correct, there are no leaks around seals or gaskets, the carb is set-up correctly, etc. That is, assume that this is all true and that the engine has but one know problem and that is the cylinders have exceeded the wear limits by at least 0.006 in. My question is: could this be the reason that the engine is running with high EGT's?

  • Re: High EGT Cause?

    by » 12 years ago

    Has it only just gone like this or is it after work being done to it...does it have duel EGTs or just single,

    Have just checked the plug colours....

    When you say high...how high,

    And is it a single or duel carb engine???

    Nick.
      
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  • Re: High EGT Cause?

    by » 12 years ago

    As Nick suggested, a little more detail would help figure it out.

    I would add,if you suspect the cylinder wear, just do a quick compression check and see if compression is within liimits.
      
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  • Re: High EGT Cause?

    by » 12 years ago

    It is a single carb engine and my friend knows about all there is to know about 2-cycle Rotax engines. I am just asking if it is possible that the high EGT's can be explained by the excess wear of the cylinders if everything else about the engine set-up is OK?

    The idea about running a compression test is a good one and I don't know if it has been done.
      
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  • Re: High EGT Cause?

    by » 12 years ago

    James,

    I doubt that cylinder wear would account for the high EGTs. Usually only one thing causes high EGTs, a lean fuel/air ratio.

    If you are sure there are no air leaks around the boots and manifold and the carbs are set up right, You might suspect the EGT probes or gauge. You may not even have an EGT problem. If you have two probes, you can try reversing the probe positions or probe wiring and determine if it is the engine or the probes and gauge.

    Bill.
      
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  • Re: High EGT Cause?

    by » 12 years ago

    Bill-Not sure but this has been going on for quite sometime and the EGT's remain high. Most anything else that folks look into have been tried and the engine starts up just fine, runs well, but has high EGT's (gages have been checked, damped, reversed,etc.) The discussion is now centered on if it is possible that worn out cylinders (which it does have) can cause a lean mixture in 2-cycle engines? My friend even has new cylinders to install but would like to find a discussion, or something, about this aspect. We have not been able to find any references to this aspect of 2-cycle engine operations.
      
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