I have a 3W 85IB2 TOC ( twin ) that I bought used. The person states it's used very little and by the looks of the engine I'd agree. The engine runs great, and I seem to be chasing the needles just a tad, but my main problem is if I go to full throttle, and then quickly down to idle, it dies. It does this even with the idle set up to around 1800 or better. If I drop the throttle quickly, but stop short of idle, then let it set down to idle slowly it is fine.

Also, it seems when I do have the needles in the sweet spot, then engine likes to smoke just a bit. I am beginning to think the engine is even broken in yet.

I am running it on Redline @ 40:1.

Thanks for any help,

Mike.

If you have the needles on an older 3w twin correct it might smoke a bit. No biggie. Bottom needle sounds rich, hence the stoppage.

That's exactly what I thought also. I would move the LS needle a tiny bit, and re-try up until the point where the motor would sag when accelerating. I'm at a loss on this one as far as coming up with an easy answer.

If you can access the carb intake, place some tape over it. Spin the engine over slow and watch the tape suck in, but if it blows out the reeds are warped causing disrupted airflow at idle speeds. Second guess would be a faulty, slow reacting spark advance in the ignition unit. Or the engine needs to be timed. Third, the throttle linkage might have a bind or hitch that a fast servo movement will overcome but a slow movment gets stuck on.

Guy,

One of the methods of checking for a correct high needle with older 3w twins was to look for a little smoke on accelleration. No smoke equalled being lean on the high. A rich low needle nearly always shut them down when you cut the throttle. Good engines just the same.

Pat, thank you for your help. I feel I have the engine running pretty well now and will see how it flies tomorrow. I was too lean on the top end. You're right, it seems to like to smoke slightly in it's sweet spot.

I have a 3w 80cs that ibought about a year ago and only have about 2 gal of fuel through it, and it does the same thing! Did leaning out the bottom end fix your problem?

Do you have your idle set at 1800 by the idle scrow or with the trim on the radio. If you have it set with the radio it will die when you come back to idle fast. Try setting the idel screew on the engine to a good idle and then give it a try.

Paul