How about a different gear ratio in one of the drives? The difference between 1.5:1 and 1.65:1 is 400-500 RPM.... Maybe swap drives around and see if it moves to the other engine.

bobl - when he swapped props before - spin in - the rpms were the same, no "engine problem". Would a different gear ratio explain that? Just asking, not sure.

I still like the idea of running one engine at a time to see if they both get to max rpm's. Easy to do, may give a clue. If they reach max rpm while running solo, then forget an engine problem unless I'm missing something. Anyway, its easy to do!

And Blue Thunder's point is right on - check where drives trim is after a run with the problem. Maybe one is out of adjustment.

But I'm still hung up on why everything was OK when the drives spun in but not when they spun out.

well today I switched props around and tried see what that did. It did the same thing (same problem)stb side 4100 and port side 4700. But this time I took some advise from you guys and ran one engine at a time and I could here the stb engine breaking up this time. Couldnt here it with both running at the same time. So goign to try plug wires and hope that might fix it. It doesnt break up at idle at all. So if its not that where should I look to next. And thanks again for all your help

Well I have changed the plug wires and changed the ignition coil. Checked the map sensor and was working correctly. and still is doing the same exact thing. any advise what to look at next

The good news is its definitely an engine problem. I'm not an engine guy - with that said - I'd start looking for a fuel problem as you have done the basic stuff on the ignition side. Put on new fuel separator filter if it hasn't been changed lately - see if you got contamination in the filter. See post from dirtyplumber for other ideas.