This question has been asked many times before, and the advice is that the chronograph mechanism should be left running to minimise wear. The same applies to the Seiko 6138 and 6139 vintage chronographs. This advice relates to the design of the mechanism and the use of a ‘vertical clutch’ – I understand that running the chronograph locks the clutch in position so there is no slippage. However, I’m obliged to Adrian Licu who has provided more information via his comments on the Automatic Chronographs page after he did some research on this issue. Although the advice to run the chronograph stands, it is also recommended that the watch is sometimes run with the chronograph stopped in order to avoid the clutch parts seizing together. Here is the key part of the information Adrian kindly included in his comments. This advice was given about the Seiko chronographs, by Al Archer a Canadian watch maker:
‘……when the chronograph is turned off, the two parts of the chronograph runner have friction between them, since the large wheel must turn for the movement to run, and the chronograph hand does not move. Running the chronograph eliminates the friction between those 2 parts, but adds other loads such as the friction between the 2 ends of the shaft that the chronograph hand is attached to (one end in a jewel, the other in the tube of the center wheel). Also, there is the added load of the minute counter ticking over. Not sure I would say off or on has the most load – I would have to have the watch on the timing machine and measure the balance amplitude in both cases to confirm if one has more load (and lower balance amplitude) than the other.
But one thing you need to do with these is to run them with the chronograph off at least every so often. This will help prevent the chronograph runner parts from seizing together.’
I’ve amended the Chronographs page to include this advice.
Sweephand's Vintage Citizen Watch Blog 
HOLA: TENGO UN CRONOMETRO CITIZEN 67-9119 AUTOMÁTICO, QUE TIENE ESTE PROBLEMA. CUANDO PARO EL CRONOMETRO FUNCIONA UNOS SEGUNDOS O MINUTOS Y SE FRENA EL RELOJ. ¿QUE ME ACONSEJA HACER?. ¿DEJO FUNCIONANDO EL CRONOMETRO?. ¿LA MÁQUINA SUFRE ALGÚN INCONVENIENTE CON EL CRONÓMETRO FUNCIONANDO PERMANENTEMENTE?. GRACIAS
(HI: I HAVE A CHRONOGRAPH CITIZEN 67-9119 AUTOMATIC, THAT HAS THIS PROBLEM. WHEN YOU STOP THE CHRONOGRAPH RUNS A FEW SECONDS OR MINUTES AND STOPS THE CLOCK. WOULD THAT I ADVISED TO DO?. DO I LEAVE RUNNING THE STOPWATCH?. THE MACHINE SUFFERS FROM A PROBLEM WITH THE TIMER RUNNING PERMANENTLY?. Thank you)
Hola Miguel, perdona que dicen que tienes un problema con su 67-9119. No soy un experto técnico, así que aquí hay un extracto del artículo de Al Archer sobre Cronógrafos Seiko que podría explicar el problema que tienes:
La mayor atracción es la Asamblea de corredor Cronógrafo – no éstos típicamente pueden realmente ser “mantenidos” en absoluto, y no siquiera se deben colocar a través de la máquina de limpieza según la mayoría de las marcas como esto lavará la lubricación aplicada en fábrica. La lubricación entre el engranaje que gira todo el tiempo y el puesto de corredor cronógrafo es fundamental, y realmente no puede ser renovada en el campo, así que si esta parte es agarrada, tiene que ser reemplazado. Cuando estas dos partes aprovechar juntos, el reloj se ejecutará con el cronógrafo, como las vueltas del conjunto, pero cuando el cronógrafo esté apagado, el reloj se detendrá mientras el engranaje grande ya no volverá. He mencionado la Seiko 6139 previamente, y te diré que nuevos corredores Cronógrafo stock viejo a veces son muy difíciles de encontrar para estos modelos. Una cosa que usted debe comprobar siempre si usted está considerando una compra es si el reloj funciona con el cronógrafo apagado en un 6139. Si se ejecuta con el cronógrafo en, pero se detiene cuando está apagada, el corredor ha agarrado y va a ser difícil si no imposible ponerlo en marcha otra vez sin un nuevo corredor
Un reparador de reloj puede confirmar el problema, pero si el embrague está agarrado necesitará encontrar nuevas piezas – probablemente de un reloj de donantes. Si se ejecuta con el cronógrafo en el reloj, entonces ¡ de esa manera, especialmente desde que las partes son difíciles de encontrar.
(Hi Miguel, sorry to hear you have a problem with your 67-9119. I’m not a technical expert, so here is an extract from Al Arhcer’s article about Seiko chronographs which might explain the problem you have:
The biggest draw back is the chronograph runner assembly – these typically can’t really be “serviced” at all, and they should not even be put through the cleaning machine according to most brands as this will wash away the factory applied lubrication. The lubrication between the gear that turns all the time and the chronograph runner post is critical, and it can’t really be renewed in the field, so if this part is seized, it has to be replaced. When these two parts seize together, the watch will run with the chronograph on, as the whole unit turns, but when the chronograph is switched off, the watch will stop as the large gear will no longer turn. I had mentioned the Seiko 6139 previously, and I will say that new old stock chronograph runners are sometimes quite hard to find for these models. One thing you should always check if you are considering a purchase is if the watch runs with the chronograph switched off on a 6139. If it runs with the chronograph on, but stops when it’s turned off, the runner has seized and it will be difficult if not impossible to get it running again without a new runner
Only a watch repairer can confirm the problem, but if the clutch is seized you will need to find new parts – probably from a donor watch. If the watch runs with the chronograph on, then you could leave it that way, especially since parts are hard to find.)
Stephen
Hi Stephen,
Thank you so much for all the info on these watches. My grandfather had an 8100A which is still in working condition, so great you provide some of the watch’s history.
Unfortunately I think the origanal strap didn’t make all the years or might have just been used up by my grandfather wearing the watch. For the rest apart from some scratches on the crystal the whatch is like new:
Thanks again for all the information about the watch!
-Bram
Hi Bram, thanks for visiting my blog, and for your kind comments 🙂 Great to hear that you still have your grandfather’s watch which I presume he has had from new. And it certainly is in very good condition, especially the black case since these are often fairly worn when they come up for sale these days. Do you mind me asking when and where your grandfather bought the watch?
Stephen
Hi Stephen,
You are very welcome! I believe he got it as new too, my grandfather also participated in sailing races and always used this watch and the chronograph function. So you can understand as this watch belonged to and was frequently used by my grandfather it has a lot of emotional value apart from the fact that it’s a great watch.
Unfortunately I am not aware when or where the watch was bought. Altough I guess it was in a jeweller in The Netherlands. And as far for when I really don’t have a clue apart from the lifespan you have described.
For your reference here is a picture of the back:
Sorry for the bad lighting.
Bram
Hi Bram – thanks for the picture of the back (made in March 1973) and for the extra info. I’m even more impressed with the condition of the watch when I see that your grandfather used it when sailing.
I’m sure it has a great deal of emotional value 🙂
Stephen
Hi Stephen
Great you can see the manufacturing date, it is the 303 number? Indeed the fact that it had been used so much in sailing and is still is in such a good state is great.
If you’re ever in The Netherlands, we can get a coffee and you can see the watch in real 😀 !
Bram
Hi Bram – yes the 303 gives the production date. The key thing is to know which decade a watch was made in to get the year from the first digit in the serial number. That’s easy with the 8100 chronographs since they only had a short production, from 1972 to 1974/5. Coffee sounds good 🙂
Stephen
Hi Stephen,
wow thanks for the explanation, great they use such a system so we can track them until the exact manufacturing date.
As I too was curious when and where my grandfather got this watch I did a bit of research and also called with my grandmother. Unfortunately I am not totally sure, but most likely the watch is purchased at the Dutch jeweller Brunott http://brunott.nl/ . The standard jeweller my grandfather went to in the time didn’t ever sell citizen, Brunott however is still a citizen dealer and was the standard place to go to for my grandfather’s mother. Unfortunately Brunott can’t look back in their files for more than 15 years ago (because of change of ownership) and there is no one from the time still available.
But everything combined I think the watch was a gift to my grandfather received from his mother.
For the coffee, you can see my mail right? If you send me a message once you are in the neighbourhood I’ll get you a freshly ground one.
Bram
Hi Bram, the case material code is also useful (BLS on yours) since this should match the case, i.e. black with steel bezel. Sometimes the wrong back has been used, and the case material code will give the game away when it doesn’t match.
Thanks for the update on your research 🙂 These models were marketed in Europe in the 1970s, so it’s very likely that yours was bought in the Netherlands.
I wish I were a bit more local to you than the UK, that coffee sounds good 😉
Stephen
Hi Stephen,
Another version of the chrono work (again Al is the author) is to be found in some comments in the following thread:
http://forums.watchuseek.com/f20/omega-smp-chronograph-advice-needed-717944.html
Very interesting picture explaining why there is wear when chrono is off and how it engages when on.
I suspect Seiko 6139 chrono assembly is very similar with Citizen’s so the same observations apply. What I find interesting is that Al believes that the balance amplitude actually goes up (instead to become smaller as it is the case with horizontal clutch). Maybe this tells us that the power reserve will actually be longer when chrono is running. I will have my first bullhead shortly and I will do some tests. I will let you know the result.
Kind Regards,
Adrian
Thanks again Adrian for linking to more info on this subject, much appreciated. The more info we have, the better it is 🙂 Looking forward to seeing your bullhead and the results of your tests,
Stephen
Adrian: did you ever test this theory? Power reserve goes up not down when the Chronograph is running? Interesting question.
Hi Thomas – I’ve not heard anything more about this. I’ll see if I can find something out….Stephen