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YS leaking fuel from the carb

Old 01-26-2004, 07:05 PM
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Default YS leaking fuel from the carb

Hi Dave,

I have a new ys 110, this is my first ys engine and my first 4 stroke. I have about 1.5 gallons of 20/20 through it and also a os - F Plug. from the beginning it seems to leak fuel from the carb after shut down and while still pressurized. I broke it in with 1/2 gallon of fuel and took it to the field. I thought it seemed to be running extremely rich and a guy at the field "tuned it" for me. He said it was extremely rich and told me to turn the regulator in 1/4 turn. Before doing this he told me to seat the regulator, count the turns while turning it in all the way, then turn it back out, then turn it in 1/4 turn from there (basically bottom it out, put it back to factory settings and then turn it in 1/4). Everyone agreed it seemed very rich at factory settings, even spitting fuel out the carb while running. Turning the reg in 1/4 seemed to help. He then turned the low speed out for a total of 3 turns and high speed at 1.25 truns (I was very concerned we were out this far from factory settings. I then put the engine on the plane and took it to the field. Although it drips fuel after being shut of, it showed characteristics of running LEAN. I would run it up and after bringing it down it would increase idle about 200-300 rpm. SO I turned the low speed to about 2 turns out and the hi speed about 1.5 turns out.

After richening it out, and the plane seems to run fine in the air except:

1. after idleing for 15 seconds and then increasing throttle you can see a pretty good stream of exhaust come out for 3 seconds or so.

2. I have the engine richened 400 rpms from max, and I get about 9000 rpms (max) and I am running at 8600 RPMS after backing off the mixture on a 15x8 prop. but the engine will not really idle very good at 2000, and sometimes dies.

3. The carb still drips fuel after shutdown while engine is under pressure.

4. I do not get any change in RPM by changing the low end needle valve setting while idling at 2300 rpm (changing the needle valve from 3 turns out to 1.5 turns out).

5. I need a new exhaust tube (I cut the factory supplied tube and added a my own tube extension, but I want to go back to factory exhaust) where can I buy one in the 92649 area code, somewhere close to huntington beach, CA?

I love this engine, it really performed EXTREMELY well on the vectorflight 66"extra, WOW it just seems to be perfect for this plane, I will probably buy quite a few YS engines going foreward, the performance jsut ROCKS, but I need to understand what is going on here.
Old 01-26-2004, 09:46 PM
Dave Shadel
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Default RE: YS leaking fuel from the carb

Try the setup proceedure at If it doesn't work properly after that, we will need to see it.

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