Motor cuts out in Heavy Seas?

[BCGrady]

I have a problem I'd like to solve.
My Boat is a 226 Seafarer Grady white Powered with a 2003 Yamaha 250 Saltwater Series 2 stroke. I have owned the boat for 10 years and it runs perfect 99% of the time. 3 times under the same conditions the engine has cut out. It has only happened in heavy weather in big swells.
The engine will always restart but can not maintain any sort of speed in the heavy up and down seas.

Any ideas? I have had it in to my local repair shop but no luck as of yet. One of the problems diagnosing the issue is it is hard to recreate. The boat runs smooth under all other conditions.

Thanks for any feedback you can provide.

 

[seasick]

I've seen this before and it was either of two causes: A clogged VST screen or a loose battery connection at the motor.

 

[lodgecreekgrady]

If the VST screen and the fuel filters are good then check for trash in the fuel tank that could be moving around in rough seas and stopping the pickup tube screen up.

 

[Clockwork]

If that is a carbed engine a lot of times its the floats.