Differing temps between 2 EGT's

[Alkemac]

I noticed the last time that I flew that there was about a 70 degree temp difference between my 2 egt probes..

Is this ok, and what could the cause be ?

[KFA]

What engine and was it like this from the beginning or did you change something?

[nickjaxe]

Is that deg c or F.

Nick.

[Alkemac]

Rotax 582 blue top, didnt change anything!

Celcius.

[Morph]

Deg C or F 70 degC is a problem, 70 Deg F is not (21deg C)

I would give the carbs a lekker service, clean them out and check that there is no constrictions in the jets etc. Check the carb boots for cracks, an air leak will lean the mix, increasing egt on one piston

If this is all OK, then check the following

The carbs are basic. They have Idle jets (non adjustable), Main Jets for full throttle(non adjustable) and then Needle Jet and Jet Needle for everything in between (adjustable)

Potentially one if the two jet needles is sitting slightly lower than the other, resulting in a leaner mix on that carb and higher egt.

First determine which of the two piston are hotter. (refer to pic) loosen 11, and turn 12 out, retighten 11. This will lift that jet needle slightly. Start the engine and check. Keep doing this in very small increments until they are within 25 deg c of each

[nicow]

Thanks for the info

[Alkemac]

Thanks Morph!

[RV4ker (RIP)]

Has it always been like that or is it new?

[Alkemac]

This is something new, only occured the last time I flew.. and I havent changed anything...

[Morph]

then check for cracks in the rubber boots

[RV4ker (RIP)]

Then something is wrong. Maybe swop the probes and see if it same.

[Alkemac]

Recently replaced them, no cracks or leaks in the new ones.

Will try swopping and see what the outcome is..

[Kalahari]

If you swapped the probes and proofed that they are fine then check the carbs, a difference in EGT is usually caused by difference in the fuel air mixture between carbs, the leaner the mixture the higher the EGT and the richer the mixture the lower the EGT, which can be caused if some bypass air are sucked in somewhere which make the mixture leaner which will result in higher EGT.

Check the needle setting on the plunger on both carbs if the circlip is in the same needle groove on both carbs and check if both plungers start to open at the same time if you push the throttle. (Same as what Morph said earlier)

Do you experience any difference in performance from the time it was balanced?

[Alkemac]

The issue that I have is that the one that was usually lower, is now quite a bit lower. 525 degrees was the usual temp for the one, while the other was at 490.. It's now at 460 - and there doesnt seem to be any performance issues..

[nickjaxe]

You say you recently changed the probs....has the prob started since this,

What about spark plug colours do that match each other pot to pot and are they the correct shade of brown....as the outside air temp goes up your EGTs will come down and visa versa, see link for more info....the more joins you make between sender and gauge to more possible errors....and note that they only read true at 75f or 24c.

Have you altered you prop in any way???

http://www.westach.com/instructions/2DA1.jpg

Nick.