Fuel flow vis EGT. M7 235B

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Cash
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Fuel flow vis EGT. M7 235B

Post by Cash »

In newly acquired Maule the EGT inop however it does have a FS 450 fuel flow meter. Will add EGT in future however for now can anyone with both in 235 carb engine give me fuel flows at different power settings running 50 to 100 degrees rich of peak? Thanks. Les
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Mark - AK
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Re: Fuel flow vis EGT. M7 235B

Post by Mark - AK »

M-7 235 B4B5 operating at cruise power at peak EGT as per Lycoming engine book, I have found that peak EGT happens right when you get the first indication engine roughness as you lean. I'm not sure why you would want to cruise at best power which is close to 100 rich of peak. This procedure works at power settings of 70% and below. This usually gives CHT of 320 plus or minus. Typical 22" at 2200 rpm fuel flow around 13.5, 20" and 2200rpm gives 12 g.p.h. Oil temps usually end up around 180 in summer - I am in Alaska. I hope this helps until you get your instrumentation set up.
Mark - AK

Cash
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Re: Fuel flow vis EGT. M7 235B

Post by Cash »

Thanks. Mark AK. I agree with you on 100 degrees rich unless your in a hurry and willing to trade fuel for time running 75%power. Any one else have some actual EGT over peak vis fuel flow at different power settings? Thanks. Les
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Rezrider
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Re: Fuel flow vis EGT. M7 235B

Post by Rezrider »

EGT is a result and the actual number doesn't matter, it's only useful for finding a peak on a particular cylinder. I fly pretty high, 5000-11,000 ft range so I can lean fairly aggressively below 75% power. With my O-540 I can get it down to 11 GPH with around 18-19" MP and 2300 RPM. I use a tiny bit of carb heat and it allows all 6 cylinders to lean out more evenly. I have a EDM 700 which is super helpful to see exactly what is going on. CHT's are what I watch closely.
Play around with it and see what you find.
Good luck.
1980 M5-235
Four Corners

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