Your problem could be due to high speed needle valve is set too lean, but to make sure it is adjusted properly, try using the following procedure to verify and adjust.
The way to properly set the engines mixture is to make sure engine has a good glow plug (OS #F or YS) no other plugs are suitable, and good fuel with at least 20% oil content. Meanwhile try not using less than a 20% nitro blend even though the instructions say it will work on 15%. The engine tuning gets much easier at higher nitro from 20 to 30% nitro.
Start with high speed needle on the rich side, and go to full power using a Tach and slowly peak the engine a click or couple clicks at a time. It will sometimes take 5-10 seconds for your adjustment to have full effect so be patient.
Find the Peak RPM and back it off to the rich side approximate 200-300rpm. The 63 should run about 10,500 to 11,000 rpm. If you don't get this high of rpms then you have too much propeller or not enough nitro. You need to pick a propeller and fuel that gives this rpm. Example the 12-7 to 12-9 APC will give this rpm. Depending of course on the fuel you choose.
Next is to take the tach and throttle the engine to a "high idle" maybe 1/4 power at 4000rpm. Watch the tach. If it surges up and down on the rpms, then the regulator is too lean. If the engine starts to load up and slow down when at the 4000rpm number, then the regulator is too rich.
Regulator adjustments are the same as the High Speed needle. IN (CW) is leaning and OUT (CCW) is richer. Make small adjustments to the regulator such as 1/8th turn at a time.
Each time you adjust the regulator you must re-adjust the top end needle to the same setting as before.
Once the top end is set properly and the regualtor is running properly at 4000rpm...its time to adjust the idle mixture.
The idle test is exactly same as the regulator test, but the rpm you want as a target is 2000rpm. At 2000 rpm if it surges up and down or speeds up, it is too lean. Richen the Air bleed idle mixture screw. If the engine idles well then starts to load up and falls off on the rpm, it is too rich, lean the Idle mixture screw.
The idle mixture screw is an air bleed screw and not a needle valve. It controls air flow not fuel flow. Because of this, it works backwards from the High Speed needle. Closing it (IN or CW) will richen as it allows less air in. Less air means richer. Opening the Low speed air bleed screw means it leans the mixture or allows more air in. So CCW rotation is leaner on this adjustment screw. This screw only works at 2000rpm...and fine tunes the low idle.
If the regulator is not set properly then this screw will have little to no effect. In fact anything above about 2300-2400rpm it will have ZERO effect on the mixture. It only works down low at the 2000rpm idle position. It only fine tunes the mixture down in the low range. |
發表於 2008年3月20日 03:27 PM
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