older 912 ul heating up

[Norm]

Not sure because I just fly mine and have never had to adjust but "drop down the needle" wouldn't that make it leaner as less gas is being allowed in the carb. Not sure on the 912 but I know that is how the 582 would work.

[oldfox]

Nope I drop the clip down that takes needle up and makes richer. I’m looking to see if I can maybe change the timing?

[jiott]

Have you checked the entire coolant system including radiator for free flow?

[Av8r3400]

How about the sender or gauge?

[kmach]

Are you using 50/50 antifreeze/water or Evans water less coolant? There is around 25F difference between them in coolant temps.



Do you have all cylinder's exhausts monitored for egt ?



Carbs out of sync can cause different egt readings on different cylinders .



High egts can mean inefficient burn in the heads. Proper plugs? gapped at what?



Prop pitch can affect heating, over pitched and you will generate heat. lugging the engine will do this also.



Did you try increasing rpms ? to 5300- 5500, sometimes this will make the engine run cooler.

[oldfox]

Ok guys I have not flushed the coolant system good idea will do only have two egts one in the front and one in the back other side of motor. Carbs are synced right on the money and by the way brand new carbs not old ones also brand new spark plugs, have not try to run high RPM . I get if the coolant is a problem but would that send the EGTs through the roof again has anyone gone fatter on the main jet ?? I have 158 jet size and a 2nd through would be to much exhaust restriction could cause this also ?? Again hair pulling shi”” thanks for the help guys anything more you guys come up with let me know.

[Dave S]

Oldfox,


Just a thought. Many times when I have done engine diagnosis (not necessarily aircraft engines) especially when a symptom can have many causes such as this puzzling situation your are dealing with, I have found it useful to go back and check cylinder health first....meaning compression - reason being that no amount of work on the ignition or fuel systems will dispatch a problem if there is a mechanical problem such as an exhaust valve developing a leak.



A cylinder problem can translate into high EGT or high CHT due to lack of cylinder efficiency. Ruling this out could help reduce the number of things you would want to consider.


Again, just a thought.

[Russell320]

Before all this started, what were the original readings?