How obvious would a 150 with 115 stickers be? 

Sticky question but, would johnny law or anybody else know the stickers were wrong?

Is this for a lake rating or a motor on the boat rating?  If it is the boat then your insurance would probably be no good.

And yes if they know anything they should be able to tell.

No law here concerning overpowering a boat.

Insurance would be hard to get.

Noticeable performance difference between the two.

If you happen to be involved in an accident you can bet the lawyers will jump on it.

I ran a 200 on a boat for years that had a max rating of 175 w/o a problem. At that time tournaments did not regulate the HP into their rules either. Got insurance on it back then w/o a problem. Probably could not get it now though.

If its cheating or breaking the law, look elsewhere for advice.  Please explain your motives.

How obvious would a 150 with 115 stickers be?

Sticky question but, would johnny law or anybody else know the stickers were wrong?

The 115 is a much slender and smaller motor.

Bad idea all around.

depends on the the model/year.

all things considered, i could think of many things worse than doctored boat stickers.

depends on the the model/year.

all things considered, i could think of many things worse than doctored boat stickers.

A lie is a lie. 

If it's one of the mid to late 80's inline six 115's then it is 150 from earlier years.  When they started rating the hp off the prop shaft instead of the flywheel, the 150's became 115's.

If you're talking later models, the the size is very, very obvious.  The cowling on the 150 is almost twice the size of the cowling on the 115.  You won't be fooling anyone with a decal swap.