ORIGINAL: shawn45
Hello guys,
I have DL50 in extra 260. The engine runs great in hi RPM but no matter what I do just can't get rid of the low end burble!!! It runs too rich on low end. It sounds good on the ground but terrible in air. I adjust the low end to the point that engine wants to quite on transition but still no help.
No my cowling is not pressurized.
On one of the threads on this forum, someone says that he has 2 of these engines and the way he manage to fix the problem is with the high end needle leaning, which I've tried and helped very little. I'm using NX 22x8, Amsoil 80-1.I understand that with these engines, you get some burble but mine is not acceptable. Any suggestion?
Hi Shawn45
I had the same problem on mine until I adjusted the needle leaver inside the carb.
The needle leaver needs to be lower than the carb base. Mine was at the same height as the base and running rich causing the mid range burble and a lot of mis-fires. I was making adjustments to the leaver a few thousands at a time and getting nowhere. Once I read the article below and set the leaver below the base by what looked to my eye about 2 mm give or take, it ran like a top, all the burble and misses are gone. It idles and accelerate a lot better as well.
I also did a spark plug test by running full throttle for a minute and shutting it off. Then I removed the plug and now it's a perfect tan colour.
Make sure you can run at full throttle on the ground for a couple of minutes without the engine running out of fuel after the adjustment. Be careful not to overheat your engine.
Bound_4_Hell
Life should
NOT be a trip to the grave with the idea of arriving safely in a well preserved body, but rather to skid in sideways, RC transmitter in one hand, a joint in the other, body thoroughly used up, totally worn out and screaming
"WOO HOO what a ride".
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Here are the instructions and a photo from the article.
http://www.geocities.com/farellus/idle_adaptation.html
The Metering System is very simple: It consists of a pivoting lever working like a seesaw with a spring on one side and an Inlet Needle (with a red rubber tip valve) on the other.
If you don't have the pressure-testing tool, don't worry, just make sure you clean the carb, blow it dry and use new diaphragms & gaskets and set the Metering Lever height; The resulting pop-off and reseat pressure will be functional as long as you don't damage or modify the Metering Spring:
1) Don't deform or cut the small Metering Spring. If in doubt, replace it with Walbro part Walbro part # 98-320-7 (OEM # 503 28 12-18; WG8 carburetor).
2) Set the Metering Lever at the correct height as explained below.
The height of the Metering Lever on any diaphragm carburetor is critical for controlling when and how far the inlet needle 'pops' open, thus configuring the engine's acceleration characteristics. If the Metering Lever height is set too high, it may create a rich condition, while a Metering Lever set too low may create a lean condition. The height of the Metering Lever must be 1.7 mm or 0.067" (WG carbs) and 1.45 mm or 0.057" (WB carbs) below the edge of the carburetor body. Walbro sells a calibrated brass plate gage to be used as depth meter (Walbro item # 500-13-1) available through most power tool shops.