2001 200 hp. idles rough runs fine above 800 rpms. when at idle if you trim up or down my volts drop to less than 12. is a bad battery the culprit or maybe a fuel pump problem?

Go to Mercury's web site they have a trouble shooting page.

where? can you post a link?

I'll look for it..

when your idling your motor should be level with the water i had the same problem and thats what was wrong

agdave, my 250 Opti does the exact same thing, and I have had a couple of guys tell me there's does the same thing.

If I trim all the way down, I lose a little voltage and then it comes back when I get on the throttle.

I had a mechanic tell me, it's just one of those noises Opti's are known for...

yes it does that, but also when you are just idling its a little rough, like a little hiccup every now and again

Have you checked your fuel filter lately? I've been helping out at the boat shop lately and the fuel filters we've seen are full of particles...You could also have a fouled plug or your carb(s) could need a good cleaning...

no carbs on this motor, but i am going to check my plugs today. runs fine over 800 rpms smooth as ever. just a slight hiccup at idle

Do you run Quikleen in your fuel if not I would recommend doing so cause a dirty direct injector will cause a hiccup at low idle what the quikleen does is keeps the injectors free of carbon build up on the injector pental...OPTI

yes sir quick cleen has been put in it since i bought it. dont know about the first owner. should i put more quickcleen in it to decarb the injectors?

Optis have been known to have a low rpm miss in them. It's nothing serious or fatal, it's just something weird in the PCM. I usually goes away when you give it a little throttle.

check carborater and spark plugs but thts the way opti r. they r porr engines i traded mine in for a johnson fast strike tht was 3 years old. best descition ive ever made. never had trouble with it. the only thing is it burns a lot more fuel