I don't think my boat's engine is running at top notch and it is a old engine, 70's or so, but one of my friends said he heard from a  mechanic that if the carbs might be dirty because I have been going through so many spark plugs and lacking power when others are in the boat.  He said to get a entire can of carb cleaner and spray the whole can into the carb.  Then let it sit over night.  Then when you start it up it will smoke for the first couple of moments but it will brun and clean up everything in it.  

Has anyone heard of this or done that?

carb cleaner might help some but since it's probably been a long time since you have had it tuned up, why not take it in for a once over?

The worse thing you can do is listen to anyone that has no experience telling you how to repair your motor. Get it checked out by someone that knows or you'll just be throwing money away changing things that may or maynot fix the problem.

good point

Carbs have to be removed taken apart and cleaned.  You can spray a case of carb cleaner in the carbs, let it sit over night and it will still make absolutely no difference.

What he was probably refering to is a decarb spray, totally different than carb cleaner. This is BRP's http://www.evinrude.com/en-US/Accessories/Product.htm?product=ENGINETUNER&page=2&category=EngineCare and you will need a couple of cans so you can do it a couple of times, letting it sit overnight between each.

After a couple of good doses, take motor to the lake, run it WOT for about 10 minutes, bring it back and install new set of plugs. When you get it back home, do a compression check. Make sure there is no more than approx 5% between highest and lowest reading.

If compression is very far off, you're wasting your money on going much further.  

I did a compression test before and it was good, but maybe I do need to get a carb kit.  It starts up just about every time on the first to second crank, only had battery problems when I did have trouble.  Just trying to get that little bit of get up and go wen I have others in the boat.