Seconds hand slight stuttering

[Chopin]

I have a swiss manual wind vintage movement (50s period; unknown maker; 17 jewels) that has just been serviced. Nothing inside looked damage but I noticed the other day that sometimes there is a slight stutter with the seconds hand. It seems to only happen in one spot, I believe, for around 4-5 seconds. But that point seems to move around throughout the day/time, perhaps it advances.

What could cause this ? Too little/too much lubrication with certain parts or potential damage ? Where should I investigate this matter in the movement ?

Forgot to mention it's a 18000 movement. By stuttering I mean that when it reaches the area that it starts to do this instead of having 5 ticks it'll have 3 larger ones, or at least that's how it looks like.

Edited February 28, 2018 by Chopin

[wls1971]

A picture of the movement and watch would help you do not say whether the  second hand is a small seconds or a large center seconds hand and if so is it  via a pinion and driven from a wheel on the third wheel arbor and held in place with a tension spring ?

I don't think It would be possible for anyone to answer your question without these basic facts I'm afraid.

Edited February 28, 2018 by wls1971

[Chopin]

I'll try and provide a picture as soon as I can. It is a central seconds hand. Yes a tension spring does hold the seconds hand pinion or whatever it's called.

[anilv]

The spring needs to be adjusted to apply a bit more tension by bending it a bit. 

Anilv

[rodabod]

Probably what Anilv suggests, however, monitor the balance amplitude before adjusting...... the increased friction from the sweep seconds spring shouldn’t affect the amplitude significantly, but something like a reduction of 10 degrees may be typical. Monitor the amplitude throughout the 60s cycle, and check that it is consistent. If it is not, then inspect the moving contact points. 

[mikepilk]

I had this problem on an Omega - really bad stuttering of the second hand.

Be careful bending it - I broke it on the Omega. I fitted a new one, and problem solved

[Chopin]

Well I eventually just lubed the area between the spring and the wheel that's connected to teh seconds hand and I think I also re-adjusted it a bit and it's now good.

Thanks guys!