the engine in our SAN 220 2006 sporadically goes into emergency run (only idle). Usually after ca. 10mins of cruise and only once a day. After that it is usually fine. 

Error code with a CodeMate is 81, various causes. 

Besides that the engine runs smoothly in all situations. 

- Do I get more information with a more expensive diagnostic tool? Or is that limited by the engine?

- What would be the usual suspects to check? 

unfortunately it's really hard to find mechanics here who have some knowledge (or tools) with these engines...

Thanks very much!

Matt

If it isn't pulling well, lopes at idle, or has sluggish acceleration - change the plugs.  These engines are sensitive to the platinum plugs.  They don't get the long use that non-marine engines get with them.  The improper burn can retard / alter engine performance and not throw any codes.  My engine has been awesome and if there is ever anything amiss, it is usually plug-related. 

Good luck.

hmm... I'm pretty happy how the engine runs otherwise, no lack of power or weird sounds/spotty acceleration. 

Thanks for the hint with the plugs, haha, one of my boat mechanics told me, I will never have issues with the plugs ;-) but he works mostly on cars

 I just came across your thread. I don’t know what error code “81” is but I do know there are only two things that will cause your 2006 engine (whether is be the standard Excalibur 5.7 or the optional ZR6 6.0) to go into “Power Reduction Mode” (“emergency run” as you call it) where it will not run above 2000 RPM. An overheating situation or a low oil pressure situation. Assuming the engine is not actually overheating and/or does not have low oil pressure you are experiencing a very common problem. You have either a faulty water temperature SWITCH (NOT sensor) or a faulty oil pressure SWITCH (NOT sensor). There is a lot of information about this on PlanetNautique.com. You can go on PN and click on the manuals/brochures section, scroll down to 2006 and find all the information you need.

Plenty of information on the limp mode here on CCfan too. You don't need to go over to PN! 

You're a whole lot better off going to PN for the manuals and info like mentioned above for your 06 GM engine. 

I do have a ZR6. 

And sorry for the mis-nomenclature ;-) wether native nor mechanic ;-) 

I guess I missed the model year, it's most probably a 2007. 

I had a look, could not find the pressure switch on the engine (it should not have one if I understand the manual...) (https://www.planetnautique.com/CorrectCraftManuals/2007/20076.0.pdf   pp. 18)

But contrary to the manual, there is a Water temp sender (R020002)

Is there a temp switch in the 2007? Any hints? thx!