Originally Posted by
Cougar429
I need a bit of help with this one. Have a side mounted 100 that I simply cannot lean enough with the LS needle to smooth out, even bottomed all the way in.
Other than a deformed jet tube or damaged needle cannot think of any reason could not drop the mixture without cutting it out completely, but it will still run, just rough.
Fuel is 15% nitro, 17% lube and used throughout the fleet.
Assuming you have already tried a new plug and adjusted the valve clearances it should run reasonably well (A bit rich) with the lsn set flush with the outside of a metal throttle arm or flush with the inside of a plastic throttle arm.
As to not being able to lean the lsn enough you may have crud built up inside the tubular portion of the lsn. That could cause a false "fully seated" feeling when screwing it in and cause all kinds of problems at other rpms too.
Another thing to check is the throttle barrel retaining screw for excessive wear. If it is badly worn the throttle barrel will extend outward further than normal causing an overly rich condition. I have never seen one worn to that degree but have heard of it.