Tuning a 4-stroke for beginners...
08-26-2002 | 02:32 PM
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From: pickering, ON,
Tuning a 4-stroke for beginners...
Hi All,
Here's how I'm tuning my saito .72. I am staying below 10,000 RPM with a 13x6, during break-in flights. I've flown about 9 times now.
I've read threads about sloppy rich, too lean black residue. Truth is I am having great difficulty figuring out where I should have the setting. Right now it's below 10,000, about 9600. It loads up so I can't stay at low idle for too long. Fly's good at 1/2 to 3/4 throttle but I see no improvement when I go full throttle. Even seems to bog down.
I read where during break-in you may have to adjust low end leaner after every couple flights. I'm going to give it a 1/4 turn this weekend.
However what I'm looking for is a beginners guide to tuning a 4 stroke.
Notes:
Can I nose up the plane at full throttle to see if there is a pitch difference OR pinch the fuel line to see if too lean?
My tach reading is not consistent, it jumps around, how can I tune to max less 400 when it jumps around a 1,000 different.
All help is appreciated.
RD
Here's how I'm tuning my saito .72. I am staying below 10,000 RPM with a 13x6, during break-in flights. I've flown about 9 times now.
I've read threads about sloppy rich, too lean black residue. Truth is I am having great difficulty figuring out where I should have the setting. Right now it's below 10,000, about 9600. It loads up so I can't stay at low idle for too long. Fly's good at 1/2 to 3/4 throttle but I see no improvement when I go full throttle. Even seems to bog down.
I read where during break-in you may have to adjust low end leaner after every couple flights. I'm going to give it a 1/4 turn this weekend.
However what I'm looking for is a beginners guide to tuning a 4 stroke.
Notes:
Can I nose up the plane at full throttle to see if there is a pitch difference OR pinch the fuel line to see if too lean?
My tach reading is not consistent, it jumps around, how can I tune to max less 400 when it jumps around a 1,000 different.
All help is appreciated.
RD
08-26-2002 | 03:23 PM
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From: Wolfforth,
TX
Tuning a 4-stroke for beginners...
If you can reach your fuel line try this. Let the engine warm up and let it idle. Pinch you fuel line for a few seconds, if the rpm's go up your low end is rich if your rpm's go down your low end is lean. I have mine set 1/8 of a turn to the rich side of lean.
You can do the same thing for the high end!
Good Luck!
You can do the same thing for the high end!
Good Luck!
08-26-2002 | 11:40 PM
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From: St. Petersburg, Fl
Tuning a 4-stroke for beginners...
08-27-2002 | 09:18 AM
#4
My Feedback: (8)
4 Stroke Tuning
High End: Use tach, lean to max rpm mixture setting and back off (richen) about 400 rpm shy of max lean
Low End: Adjust to obtain low idle with smooth transition to full throttle. I prefer to keep my idle slightly lean so it doesn't load up at extended idles.
Pinch test not reliable for 4 strokes and is best used with 2 strokes. If you can hear a significant different in engine speeds when you do the pinch test on a 4 stroke, you are too rich to begin with. A 400 rpm rich setting is barely, it at all, noticeable with a pinch test on a 4 stroke.
Low End: Adjust to obtain low idle with smooth transition to full throttle. I prefer to keep my idle slightly lean so it doesn't load up at extended idles.
Pinch test not reliable for 4 strokes and is best used with 2 strokes. If you can hear a significant different in engine speeds when you do the pinch test on a 4 stroke, you are too rich to begin with. A 400 rpm rich setting is barely, it at all, noticeable with a pinch test on a 4 stroke.
