The port throttle is at 52%, While the starboard throttle is at 38% when running at 3000 RPM both engines.
The compression is in normal range in all cylinders, and there is spark from the coil to each cylinder.
The throttle levers stay approximately 1/2 inch apart, and the speed at the top end suffers.
Any advise?:thankyouthankyou

Did you have a drive rebuilt? I had a friend who had a drive rebuilt and the person whom rebuilt it put in the wrong gear ratio so one drive had 1.5 and the rebuilt had 1.36. Also check props for actual pitch/rake/diameter to insure they are identical. Do both motors make the same boost at WOT?

I had a miss from a fouled plug that I didn't catch for a whole season, ended up glazing up the rings in that bore and had to do a rebuild... I cruised at 2600 to 3000 rpm and when running on 15 of 16 it didn't hurt performance so much so it went unnoticed, hell it even idled smoothly, found it out when I added multi-spark ignition and hotter coil, that cyl fired and kept running, but now smoking to beat the band, hence the rebuild, be careful!

What I noticed was the stick miss match and kept digging until I uncovered it. The "fouled plug" never really looked "fouled" it just would stop firing.

Are the throttle cables the same length? one longer than the other can do something like that.
Also had a set up were one engine used less throttle than the other made some timing changes and the other side ran a bit better. Throttles were not off that far though.

The gear ratio in the drives are the same, we replaced the throttle position sensor at the suggestion of Skogren,
the plugs all have spark. We checked the cables at the engine side, with no change on adjustment. We are considering
working with the cables on the dash side-any ideas or comments, as the situation remanins unchanged,

The throttle cables have been reworked, and we are running 5100 RPM at 90 MPH with Hering 38 pitch
6 blades. We are thinking of changing to Hering 35 pitch 5 blades. Any Ideas?