Hi. I know there has been a lot of discussion about dual pmag's and fm150's on io370/375's but I'm hoping to get a definitive answer, if thats even possible with these engines!
I have an io370 with dual pmags and fm150 afp fi system.
After starting from cold the engine runs fine but threatens to cut out after a few seconds. If I manage to keep it running it runs with steady rpm with fuel flow showing about 5-6 gph, 1200rpm. After it warms the ff drops to maybe 1gph and starts to run rough. After a flight, during taxi in I have seen it even lower, less than 1/2 gph and it runs rough. Over about 1400rpm it smooths out again tho. On approach there is also some misfiring but at higher rpm. Max ff I have seen is 15gph on takeoff and fulll power climb which I believe is too low. Cht's in cruise are around 380 but rise to 450 during climb. The engine only has about 6-7hrs. I haven't been able to check the mixture as described by afp as it doesn't run evenly enough to allow this. Reducing mixture on the ground whilst idling doesn't appear to do anything as the engine runs too rough to tell. I have checked for intake leaks but there isn't anything obvious. All cylinders temps are fairly even, none stand out.
I slightly retarded the pmags which are now timed at about 22.5 btdc.
Baffles all seem good, no gaps and nice pattern on the top cowl, the same as all the other rv's on the airfield which all struggle to get the temps up.
I had to change the oil cooler for a 13 row which has helped oil temps.
I think that its running too lean but I don't know what could cause the ff to drop as it warms up and also how to reduce the chts during takeoff/climb.
Any ideas?
Thanks
I have an io370 with dual pmags and fm150 afp fi system.
After starting from cold the engine runs fine but threatens to cut out after a few seconds. If I manage to keep it running it runs with steady rpm with fuel flow showing about 5-6 gph, 1200rpm. After it warms the ff drops to maybe 1gph and starts to run rough. After a flight, during taxi in I have seen it even lower, less than 1/2 gph and it runs rough. Over about 1400rpm it smooths out again tho. On approach there is also some misfiring but at higher rpm. Max ff I have seen is 15gph on takeoff and fulll power climb which I believe is too low. Cht's in cruise are around 380 but rise to 450 during climb. The engine only has about 6-7hrs. I haven't been able to check the mixture as described by afp as it doesn't run evenly enough to allow this. Reducing mixture on the ground whilst idling doesn't appear to do anything as the engine runs too rough to tell. I have checked for intake leaks but there isn't anything obvious. All cylinders temps are fairly even, none stand out.
I slightly retarded the pmags which are now timed at about 22.5 btdc.
Baffles all seem good, no gaps and nice pattern on the top cowl, the same as all the other rv's on the airfield which all struggle to get the temps up.
I had to change the oil cooler for a 13 row which has helped oil temps.
I think that its running too lean but I don't know what could cause the ff to drop as it warms up and also how to reduce the chts during takeoff/climb.
Any ideas?
Thanks