SuperCubDriver
Well Known Member
I just completed my RV-8 - posted in another thread.
The airplane has a AerosportPower IO-375M1S low compression with 2 P-Mags, Superior sump and Airflow Performance FM-150 Fuel Injection System with purge valve.
I?m having two issues and looking for help and advise:
1. Idle quality is lousy, RPM is fluctuating. When advancing the throttle engine smoothes out at about 1400 RPM. Leaned the idle with the adjuster screw on the throttle body with no help. mixture lever is almost unresponsive. Checked for intake leaks visually, all bolts are secure and no visible gap. Boost pump on or off doesn?t matter, fuel pressure without boost pump is around 15-27 psi, with boost pump on 35 psi.
Is there a good and simple way to check for intake leaks?
I did not touch the ignition yet but left, right or both mags is just the same.
2. When advancing the throttle without the boost pump at around 2000 RPM the fuel pressure is going down to 5 psi followed by decreasing fuel flow, so the engine does not power up with only the engine driven pump. It accelerates fine with good power for a very short time til the fuel flow drops.
With boost pump on it accelerates normal with normal power output (FF 16 GPH). I once disconnected the engine driven pump and operated the engine with only the boost pump. Idle problem is still present then and the engine is powering up.
So if anyone had a similar experience or ideas how to approach these problems I am very interested in getting directions.
Thanks - Hermann
The airplane has a AerosportPower IO-375M1S low compression with 2 P-Mags, Superior sump and Airflow Performance FM-150 Fuel Injection System with purge valve.
I?m having two issues and looking for help and advise:
1. Idle quality is lousy, RPM is fluctuating. When advancing the throttle engine smoothes out at about 1400 RPM. Leaned the idle with the adjuster screw on the throttle body with no help. mixture lever is almost unresponsive. Checked for intake leaks visually, all bolts are secure and no visible gap. Boost pump on or off doesn?t matter, fuel pressure without boost pump is around 15-27 psi, with boost pump on 35 psi.
Is there a good and simple way to check for intake leaks?
I did not touch the ignition yet but left, right or both mags is just the same.
2. When advancing the throttle without the boost pump at around 2000 RPM the fuel pressure is going down to 5 psi followed by decreasing fuel flow, so the engine does not power up with only the engine driven pump. It accelerates fine with good power for a very short time til the fuel flow drops.
With boost pump on it accelerates normal with normal power output (FF 16 GPH). I once disconnected the engine driven pump and operated the engine with only the boost pump. Idle problem is still present then and the engine is powering up.
So if anyone had a similar experience or ideas how to approach these problems I am very interested in getting directions.
Thanks - Hermann