Exhaust gas temp gauge?

[markmn]

I live in minnesota and wondering if an EGT gauge will tell me if I am running lean in the cold temps?

What is a normal range for the 912? I think the book numbers were 1450 to 1670? Is this correct?

Has anyone ever changed the main jets for very cold operation?

 

Thanks,

 

Mark

[Roger Lee]

Hi Mark,

 

EGT's can give you good info, but it should be included with other engine running info and OAT's to form a good picture. Knowing how to interpret this info can be misleading to some. The EGT's do help in determining leanness or richness, but your OAT can play a part here and all the engine info should be included before making any decisions. Normally the EGT's on a 912ULS may run between

1380F-1480F for what you might call normal depending on altitude and OAT. Given extreme cold OAT it may run even cooler down in the 1200's, the CHT's and oil temp will most likely be fairly cool, too. If it is then something should be done to raise those temps if you are going to fly day after day in the cold. I would leave the carb needle alone unless you are having extreme mag drops and concentrate more on blocking some of the cold air through the radiator. Until you raise the temps by reducing some of that cold air flow then doing any adjusting may be hazardous to your engine. This info also needs to be put in context depending on what plane the engine is on or in. If it is a tight cowl like the CT that changes some things verse a plane that has a fully exposed engine. In your part of the country I would absolutely have a Tanis engine pre-heater and tape off the radiator to the point of bring the temps back into that normal range.

[GlennM]

Fuel has something to do with the exhaust gas temperatures, also. My EGTs are about 100°F lower when I run 100LL. I ran roughly 1410°F and 1320°F EGT yesterday at 5100 rpm, 53°F OAT, and 1800' MSL on mogas.