Over heating on Rotax 670

[Knuckledragger 135]

I believe the pitch is set at 12.5 degrees static to limit rpms at 6200

Its ok to set the static rpm a little higher to reduce the prop load, to see if that helps temps.  As others have said, seal the cheek rads and make sure you have a good lip pulling the air out the bottom of the cowl (and through the rads).  Also consider adding a kitfox belly rad inline with the cheeks.  Mine (a 582) had this but ran too cool so I took it out.  You may have just enough extra juice to need the extra cooling capacity.

Edited 27 Dec 2015 by Knuckledragger

[Knuckledragger 135]

You might be blocking a lot of the exit opening out of the bottom of the cowling and also looks like you had to remove the lip that creates the low pressure area.  You may have to open it up more and add another lip.

This might be a stretch but you have incredibly low EGT's.

That can indicate either a too rich condition, or too much load. if you are in a too much load condition, you might be able to pull the pitch back a bit, bring the EGT's up where they belong, and in doing so produce less heat because the engine won't be working so hard.

+1 to both of these.

[rdooley79 28]

Agreed on both points, check your static rpm/pitch.

I have a 670 and was having over rich/temp tuning problems until I got my pitch just right. The 670 is sensitive to proper prop pitch and it's only a 1.5 degree window that my engine runs properly. Prop pitch is a very often over looked factor for a good mixture. The static RPM I get is right at 6325, which works nicely for takeoff in summer here in CO. This also has an added benefit of leaning the mix to where the EGT's are running right at 1050-1180 all day long.