Whipper,
First and foremost remember, I HAVE OMC's, not Merc. And nothing is absolute!
First, you got even compression readings. Good. As to what they should be on your engine, don't know. Your Gage and my three guages all will read differently, Yours is high and even!:smile
When your using the dial indicator you are verifying that Top Dead Center(TDC) is 0 on your flywheel. Correct?
On an OMC I remove all spark plugs.
Screw a piston stopping tool into #1 cylinder.
Rotate the flywheel till the piston comes up against the tool.
Mark the flywheel where the timing pointer is indicating.
Rotate the flywheel the opposite direction till the piston again comes up against the tool.
Mark the flywheel.
Measure the distance between the two marks, divide that in half. That half way mark should be the zero mark on the flywheel.
If it isn't I move the pointer and start over again until the zero and the pointer are aligned.
"One suggestion was that the magnet the presses inside the flywheel some how is moving and at speed sliding a bit not alowing full advance at WOT or something like that? "
Whipper, again I'm not a Merc Guy so take this with a grain of salt. My thinking is if the signal magnet has rotated it isn't signaling truly in relationship to TDC.
Lets say this magnet spun retarded 10 degrees.
You set the TDC mark with the dial indicator to zero.
When you put the timing light on the engine and when it flashed it showed at 26 degrees, butt with the magnet 10 degrees retarded the real timing would be 16 degrees.
OK, that said. What kind of timing light are you using. I don't trust timing lights that have the capability to change the setting with a dial. Just a button to make it flash thank you!
"Would the TPS adjustment couse any of my problem? "
Throttle Position Sensor tells the computer where the throttle is. Idle, 1/3, 3/4. Wide Open Throttle.(WOT).
On autos, at Idle it's signal is used to adjust mixture and timing. If it isn't correct both fuel and timing are not correct.
On my SDS (Simple Digital System) EFI system TPS signal is only for fuel mapping. I believe on the Merc that the TPS is used for only fuel mapping. Could be wrong, don't know.
"Also Seeing that I have spark on all cylinders does that eliminate the stator and the switch box?"
As long as you have spark at the correct time for the given RPM, I would say yes.
"Im borrowing a high end muti Meter tester from work tomorrow to take some voltage readings and sugestions were to start."
With the correct tester and the correct method from the MERC Manual, thats where you start.
Blue is a pretty color for a coil,
, as to if their good or not. Don't know but you likely could have a coil breaking down under load and also high RPM.
Is one plug different then the others most of the time, color, washed clean, wet. I've chased my tail a few times because of water getting into a cylinder at different times.
Setting timing. I always have it strapped to the trailer, IN GEAR then REV it. On my OMCs you have to go above 5,000 to make sure as the flywheel can lift and give a Gull Wing effect which can change timing. Really gets peoples attention.
On a boat it's really hard to check for a cylinder thats misfiring some of the time, coil,plug spark plug wire, boot insulation. What would be nice is to not have splashing water and have a clear view of the back of the engine. What I have done is run the engine in a tank, and in the dark watch for spark leakage. Spark plug wires get this blue halo around them sometimes. If you fill a spray bottle with water and a little salt(helps conduction) spritz a little carefully around the coils and wires and boots, sometimes you can get them to spark leak. I only say this is what I do, not saying anyone else should.
"Also should i check timing with the acu disconnected at all?"
I don't have a clue!
If the problem was there both with the ECU and the ACU and the problem didn't change, I doubt it is in the fuel side. You said you richened it up and leaned it down without change so there again doubt it's the problem.
Engine needs basically three things. Compression, spark at the correct time and fuel in the right amount to run.
Whipper I'm not there, so you are on your own. I'd, recheck how the zero mark is set and set it. Then I would set the timing to spec with a light, in gear at above 3,000 rpm. Warm it up, make sure the rich/lean wheel is set correctly and then change the plugs. Run it a short distance, see how it feels now. Chop the throttle check the plugs.
Don't do like I do and burn it down going to far since it runs good. There a saying. It runs best, just before It goes BANG!!!!!!
