Saito FG33 R3 leanging out at full power
10-08-2018, 05:11 AM
#1
Saito FG33 R3 leanging out at full power
Hello guys,
Before I send the engine back to Horizon I want to check on here to see if anyone can give me some ideas to try.
So I have a 33 that has been modified by Ray English, I am running the recommended Oil at the recommended mixture as per Ray and spinning the recommend prop by Ray as well. So it’s been set up according to Ray and properly broken in.
The problem I have been having is that at full power it drastically leans out and the RPM sags ALOT. I am getting 7000RPM static on the ground. (Before it sags). With the needles set to the recmeneded settings it won’t take the throttle at all, and quits pretty much off idle. I have to set the low needle at 10.5 turns and high needle is set to 1.5 and that gives reliable running with the exception of the leaning at high power setting. No matter how much I open either needle I get the same result. With those settings it’s the best I I can get.
To me it seems like there is an air leak somewhere and at high RPM it’s drawing in more air and causing it to lean out. I sealed the tube connecting the carb to the engine to make sure that’s not the source of the air leak. I am pretty sure it shouldn’t be each intake tube, but not impossible either. Could there be something wrong with the carb?
Any suggestions would be helpful as I have run out of ideas to get this engine to run right.
Before I send the engine back to Horizon I want to check on here to see if anyone can give me some ideas to try.
So I have a 33 that has been modified by Ray English, I am running the recommended Oil at the recommended mixture as per Ray and spinning the recommend prop by Ray as well. So it’s been set up according to Ray and properly broken in.
The problem I have been having is that at full power it drastically leans out and the RPM sags ALOT. I am getting 7000RPM static on the ground. (Before it sags). With the needles set to the recmeneded settings it won’t take the throttle at all, and quits pretty much off idle. I have to set the low needle at 10.5 turns and high needle is set to 1.5 and that gives reliable running with the exception of the leaning at high power setting. No matter how much I open either needle I get the same result. With those settings it’s the best I I can get.
To me it seems like there is an air leak somewhere and at high RPM it’s drawing in more air and causing it to lean out. I sealed the tube connecting the carb to the engine to make sure that’s not the source of the air leak. I am pretty sure it shouldn’t be each intake tube, but not impossible either. Could there be something wrong with the carb?
Any suggestions would be helpful as I have run out of ideas to get this engine to run right.
10-08-2018, 10:00 AM
#2
Before shipping it to HH, I would check the two O-rings on each intake tube to make sure none of the six O-rings are nicked. All it would take is one leaky O-ring to lean out the fuel mixture at full throttle. A similar situation happened with my FG20, wouldn't idle properly no matter how I adjusted the LSN and the engine would sag and die between 1/2 and 3/4 throttle. The fix was replacing 1 of the nicked O-rings on the intake tube; also make sure the O-rings are generously lubricated before reassembly.
10-08-2018, 11:38 AM
#4
Before shipping it to HH, I would check the two O-rings on each intake tube to make sure none of the six O-rings are nicked. All it would take is one leaky O-ring to lean out the fuel mixture at full throttle. A similar situation happened with my FG20, wouldn't idle properly no matter how I adjusted the LSN and the engine would sag and die between 1/2 and 3/4 throttle. The fix was replacing 1 of the nicked O-rings on the intake tube; also make sure the O-rings are generously lubricated before reassembly.
Yes, that was my next item to have a look at. I had inspected them not long ago, but will do so more closely to make sure.
10-08-2018, 11:41 AM
#5
The engine is installed in a H9 20cc corsair. It’s well baffled and I am running telemetry. Temps vary between 90-130C during the flight. So it should not be overheating. It happens on the ground shourtly after start up, of course I let it idle and warm up before going to full power, but it happens pretty much right away. It’s pretty consistent.
