# Bulova Accutron 218 runs too fast, is it wrong battery?



## fyndi (Aug 24, 2012)

I just bougth Accutron 218 with 218D movement from year 1967 (M7), but it is running too fast. It gains 10 mins per day. What could be the reason for such a big gain, could it be wrong battery or what? I heard that the original battery was 1,35V and today they are 1,55V.


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## lvt (Sep 15, 2009)

I don't know what could have been the cause, but I think battery voltage shouldn't significantly affect an electronic time keeping device's accuracy.


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## odd_and_vintage_fan (Dec 4, 2014)

Disclaimer: I'm just a hobbyist who really likes my Accutron 218.

10 minutes off per day is into professional fix territory. If when it arrived you put a new battery in, did the battery you took out look like either of these?














If the previous battery looked like either of those, it hasn't been serviced since Mercury batteries were outlawed. It's overdue for service.

There's a great resource here for learning about the movements: 
The Accutron Watch Page

The Accutron Index Mechanism page will help to explain what's going on. If it was set up for a 1.35v battery, the amount the index finger moves with each stroke of the tuning fork was set up (phased) for that amplitude of the tuning fork. The higher 1.55v going to the electromagnetic coils causes greater amplitude of the fork, meaning the index finger pulls additional teeth on some strokes. This translates into the watch running fast.

Considering you just bought it, it's not running to spec, and it means something to you, I'd recommend getting it professionally serviced. Costs will run in the neighborhood of $200 and it'll be good for another 5 years. During the service, it will be re-phased for a 1.55v battery and the index finger will stop pulling additional teeth. You won't need to pay 5x as much for an Accucell each year as a bonus. (I've read some early 214 movements can't run on a 1.55v battery due to the construction of the tuning fork, but all 218 movements can.)

You can search Accutron Service on the Accutron, Bulova, Caravelle forum for ideas where to send it for service.

Hope this helps. My 218 was running poorly when I got it, but has been an excellent timekeeper since getting serviced. It loses a second every other day, which is easily fixed by angling it 12 o'clock down overnight in a watch box.


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## james.laskowski (Feb 15, 2018)

If your watch is running 10 minutes fast, per day, it is definitely time for cleaning and lubrication. The actual cause of the problem in a situation like this is almost always the indexing mechanism. Simply having a little dirt or debris on the index, pawl fingers or the teeth of the index wheel can make the watch run unreliably. In addition, the tuning fork is probably trying to push a dirty movement. All the dirt and gunk that builds up around the jewels and pivots increases the resistance of the index wheel. This can cause it to momentarily skip teeth while indexing. Get your Accutron cleaned, lubricated and the index adjusted by a competent professional and it should run just fine.


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## fyndi (Aug 24, 2012)

I didn't change or put in new battery, it was already there. So I don't know which kind of battery it is. But I have a picture of it, maybe that could tell something?


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## odd_and_vintage_fan (Dec 4, 2014)

Looks like a new battery to me. It's possible the seller put it in, saw the watch was running, and said good enough. Get it serviced and it'll run like a champ.


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## minuteman62 (Jul 18, 2015)

It needs serviced and Phased .


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