a bit of a miss... when cold

[55'Fleetwin7.5]

1957 35 hp lark. Took it out today. 57 degrees. When it started, it was kinda missing or idleing rough (consistent, rythmic pattern). I got her in gear and ran it a while to warm it up. The symptom went away... Anything I should do? or just normal, get used to it... My midlle range, as I throttle up, has a bit of a "lag" for lack of a better term. My "choke plate to advance adjustement" may be the culprit... My notched mark is about 1/4" off the pointer when the butterfly begins to open. I don't spend much time at this speed anyway... but it is noticable... Any advice?

 

[lbentz]

Re: a bit of a miss... when cold

Ahhhh, a '57 Lark, huh. Excellent old motors. I think you may just need to open the low speed jet, just a tiny bit to eliminate that.

Typically, the top jet (low speed) would be 1 1/2 turns out from the seated position and the bottom jet (high speed) would be 3/4 of a turn out from the seated position. Be very careful when you turn them in to the seated position. Seat them lightly, because if you do it too hard, you'll damage the needle and seat.

If it still misses at start up, a 1/4 turn out more should help 'er. Take good care of that jewel for me.

Leon