Here are samples of the screen display from the controllers.
Port
Starboard Engine
From post number 91 Starboard Engine.
Hi Ted, I just took some (a lot of) time to read through this whole topic and to be honest as far as cooling goes, most of the time I kept thinking only after you where able to get the engine back under 180 degrees was you seem to have an issue with your starboard engine and it's taking to long to get up to engine temp and typically not hot enough for the closed cooling system these engines tend to run at while using a heat exchanger system with antifreeze. My past personal experience has been that closed cooling sometimes tends to want to run about 10 to maybe as high as 15 degrees warmer vs standard cooling at lower speeds when all is working correctly.
Also looking at your diacom readouts shows me that the port engine is running within spec and the starboard engine is running behind spec.
Your port engine temp reads 157.1 degrees via the more trust worthy ECM scan tool/ECT temp sensor with 13.60 minutes engine run time while the starboard is only at 136.9 degrees at 13.65 minutes. That's to cold for these engines specially within this timeframe. Typically on non closed cooling engines, I'm used to seeing 163 degrees at 8 minutes of idle speed only from start up...No throttle advance at all...Just let it idle and watch the idle RPM drop from the 700 RPM range down to 600. That mentioned, the drilled out holes could be having an effect with engine temp to timing ratio for warm up.
I would recommend putting in a new thermostat in the starboard engine. While the drilled out holes shouldn't be necessary, be sure to use the same size holes in your new thermostat on the port engine for best comparison....Because I understand your concerns with getting coolant to the exhaust system in a timely manner though there should/would also already be a bypass built into the T/housing...Had it been original Merc OEM?? A new T/housing came with the CC kit correct?
Spark advance is known to jump around anywhere from -2 degrees up to +10ish degrees at idle on average at normal 600 idle RPM.
The fuel mixture status Lean or Rich indicator isn't set up in the MEFI systems so you can't go by that.
Injector pulse width at 2.5 ms is close to what I recall seeing for this engine model. More used to seeing 2.1 ms on the 502's though but still okay.
Your starboard engine RPM is to high at 654 and that is due to the low engine temp. Once both engine see 163, they should level down to 600 rpm with a small +/-flex of .5ish rpm.
IAC readings have always been a small issue of obtaining solid readings as they've been all over the board. If it's running/not dying, surging, etc., etc. and your seeing some movement on the scan then honestly it's good.
At this time I can't recall seeing/reading anything special about the Fuel Regulator testing's via a service bulletin. The one thing you're supposed to do with the engine running is remove the vacuum line while watching the fuel psi gauge to see if the psi goes up 3 - 6ish psi.
You could also connect a hand held vacuum pump with a gauge connected to it and change the vacuum to the regulator and see if the fuel psi changes..... I'm sure you recall my old signature line saying buying OEM parts may just save you $$$ in the long run.
Besides a heat concern, you never did report a low on engine power or RPM on either engine which you'll need to be running at WOT to know for sure if one engine seems down on anything or truly running to hot.
If you're still going to keep searching for a running to warm issue then here's two things that you may want to visually inspected somehow but won't be easy specially with the boat in the water. One is somehow try using your inspection camera and search the rear transom water inlet hose fitting for corrosion blockage...Also inspect the internals of the water circulating water pump at the front if the engine. In rarer cases its been mentioned that switching from sea water to antifreeze wears out the pumps blades quicker should you had not installed new circulating pumps with the closed cooling system.
One thing that looked sort of kinked in one of your photos of post # 22 was the little hose that typically runs between the intake manifold and circulating pump. It's re-routed using the brass fittings...That could be a possible contributing factor too of a possible heat difference should it really be kinked too much.
Does your closed cooling system have the bleeder valve typically found on the thermostat housing such as # 16 for example? Maybe air in the cooling closed system
http://www.mercruiserparts.com/bam/s...31663/1948/150
Here's a refresher course for you on the closed cooling filling system
COOLING SYSTEM - boatfix.com
What temp thermostat are you running?
One test you'll want to perform is with the diacom connected to one engine at a time, keep an eye on the engine temps vs what you are seeing via the temp gauges. Sometimes the two don't agree with each other and the ECM sensor tends to be more on the accurate side.
