I had a bit of higher RPM sputtering when a fuel pump relay started going bad. Just a thought… Good luck.

I am not experienced with small blocks but turning the dist CCW will advance the timing? It ran better? Looks like a timing issue?? Did you get a timing light on it and set it to spec? I would not be running this thing anywhere near full throttle without getting the timing dialed in properly. If this is an EFI motor than than the base timing needs to be set. Check for full advance as the engine is revved and make sure it is also to spec. Maybe the knock sensors are retarding the timing? Bad gas? Could be a million things causing this. Get a tech or a friend with some diagnostic stuff to check everything out.......

Don't risk frying your motor bud......

Good information. Now that it is back on the trailer I can do some checking. Needed to check what Mercury said made an sense. It does not seem like the correct way to do it. Motor still under warranty and most likely will go back to the dealer.

Timing light is critical. I don't guess at timing. Asking for problems.

I Agree...since this is a efi motor, there really is nothing more that I can do, without proper tools. Not like the old days where I could slap a timing light on and turn it over....

Sure ya can. Distributor less ignition is a different story. Still a timing light and twist of a distributor. Might have to add a jumper somewhere for true time but not that difficult.

?? There is no timing mark, and no specs on what the timing should be...All it says is that the timing can not be adjusted.

Learn something new everyday. If yours is efi it is adjustable. If mpi it needs to be done at a dealer.

http://www.justanswer.com/boat/3ie76...-1-efi-at.html

Really my fault for spouting off letters that are wrong...for some reason I always want to use the EFI moniker for anything that is injected.

My motor is a MPI...

When you move the distributor on that engine you are not adjusting the timing. The timing is fixed, and referenced from the reluctor wheel on the front of the crank, and the curve is in the calibration. The distributor needs to be properly phased so that when the Ecu tells it to spark, the rotor is close enough to the correct terminal in the cap. As load and rpm increase, the distance between the rotor and post in the cap can become too far apart for the spark to jump, and it acts kinda like a rev limiter dropping spark. They usually run best when cranked ccw until the mounting boss for the cap contacts the back of the intake. (About as far as you can go)