So I got my marathon GSAR back from servicing. They replaced the crystal, bezel, dial & hands (all the glow in the dark stuff). And I’ve been wearing it daily since maybe March/April. I do remove it at night. But it’s been losing 2 minutes each week-consistently.

That’s not a problem. I never paid attention to it before & I wore it for years. I just don’t know if that is a normal amount or if I’m expecting something that isn’t within reality for an automatic watch.

I do a lot of sitting now vs when I got the watch in 08. And I take it off at night and lay it on its side facing me.

Laying it on it's side with it's crown up will normally cause it to lose time. Laying it flat with the face up will cause it to gain time due to less gravitational forces working against it versus crown up. Still, 17 seconds per day seems like a lot.

I would think they would have regulated it during the servicing but maybe not. If it were mine I'd put in on the timegrapher and see what it says. I get +/- 2 seconds a day with my Miyota and Seiko movements so I'd expect similar with the SW200 in your watch (I assume that's what it has). I've mostly dealt with Seiko and Miyota but your SW200 should be fairly easy to regulate assuming you want to do it yourself.

A watch that loses 2 minutes a week is still 99.98% accurate. Try setting the watch face up at night as Ogie recommended. If it still loses time, then you will need to try different positions.

Want to nerd out on the math?

To calculate the accuracy percentage of a watch that loses 2 minutes a week, we can use the following steps:

1. **Determine the total minutes in a week**:
- There are 7 days in a week, and each day has 24 hours.
- 7*24*60 = 10,080 minutes

2. **Calculate the percentage of time lost**:
- The watch loses 2 minutes out of 10,080 minutes.
- (2/10080)*100 = .0198

3. **Determine the accuracy percentage**:
- Subtract the percentage of time lost from 100%.
- 100-.0198 = 99.9802


So, the accuracy percentage of the watch is approximately **99.98%**.

2 Min a week is a little much!

I sent my GSAR back to repair /replace the crown, they tuned it up. Im **about** +/- 5 sec a day.

I'd give Marathon a call

I don't know if Marathon boasts COSC certification, but if it does, that is unacceptable for a recently serviced watch, and it may be way out of spec anyway for a recently serviced watch.

I had a Breitling Hercules that they just could not figure out what was wrong with it. It went back three times under warranty and by then I couldn't stand the sight of it anymore, traded it for a Sinn U2.

Two minutes a week is a lot, especially if it loses time. I would ask to have it recalibrated and error on the fast side.
I can handle a watch that runs a little fast as I can hack the seconds each morning. Running slow means I have to set the watch everyday, which is not acceptable.

If it is chronometer certified, that is too much. If it isn't it is still more than it should be, but it isn't really too bad. Ask if they regulated it when they serviced it.

IIRC, Marathon does not certify their run-of-the-mill watches.

This watch has either an ETA 2824-2 or a Sellita 200 movement depending upon year of manufacture, neither of which would be a whole lot more accurate in stock condition. Now given the watch is several year old, it probably need a movement service during which it might be possible to regulate it to a much more accurate state depending upon wear and movement condition.

Mechanical movements are not set and forget pieces.

RMD

From the Marathon website it appears the GSAR is not chronometer certified. My recently (2-3 years ago) serviced Rolex GMT Master II is chronometer certified and I can't remember the last time I had to set it.

I had been craving an automatic watch for a long, long, time. I finally picked out a watch that I thought would be a great compromise between solid reputation and affordability, a Sinn. It’s ability to keep time bothered me.
I contacted Sinn, did a time study and was given the predictable “within specs” response. I now wear an Apple watch.

Thanks guys, I will lay it on its back when I take it off and see how it goes.

That is a lot, and I doubt a change of position makes that big a correction. Does sound like not properly regulated.

While Temple may not have a watch repair shop you trust, there are several in Austin and DFW areas. you might consider dropping off with them to regulate next time in the area, or send back to Marathon. Shipping to them or independent shouldn't be too bad on that watch even with insurance.

I only own one non-mechanical watch, and they are all much tighter spec than that. Only two are COSC certified.

As long as you can get the back cover off, it's pretty easy to regulate an auto watch. Plenty of youtube instructions..