400watt MH problem

So I have a Sylvania ballast hooked up to my MH over my tank and just replaced the bulb that came in it with a 14k Hamilton bulb. Both the ballast and bulb are 400watt. When I plug it in it lights up and goes through the spectrums and everything until it reaches what it should be then begins to flicker and finally turn off. If I keep it on it will light back up every 15-20 minutes and do the same thing. What could be the problem?

 

Not running a ballast designed for aquarium bulbs with an aquarium bulb

 

I believe that it's a magnetek ballast. It says M400/MULTI-I/D and 47172-4 on it. I don't know if that means anything to any of you? It also says that it works with M59 and H33 lamp types. Is it that I don't have the right ballast? I bought it from a fellow reefer who uses the same set up with a Plusrite 14k bulb.

 

Bump....

 

The starting capacitor is to small , weak or just bad replace it or bump it up . Like if its a 5 mfu then go to a 7.5 muf Cap.

 

Would this kind of capacitor work?
Intertherm part # 622132 7.5 muf Blower Capacitor - eBay (item 350130593078 end time Apr-23-09 09:20:25 PDT)
Eh I dislike having to gut my fixture, but if that would work, it would be amazing. Thank you, Tangster, for locating the problem.

 

First I will say, leave the ballast on for a few hours some times as the bulbs burn in, it can shut off. But if the ballast has a problem it is normally the cap, but I would highly suggest changing it out for another cap of close to the same capacity. You will need to look at the cap in the ballast and see what size it it. If that cap in the ebay listing is the correct size for your application it will work.

Kim