stratman

2000 Mercury Racing 800SC's orginally from NC now in Michigan. Anyone have a baseline Jetting Package for Great lakes?? thanks...

articfriends

iTrader: (1)

were they jetted correct for sea level in NC? We are 590 feet above sea (you would need slightly leaner)level here but our ambient average temp is mid 70's theres should be mid 80's,it should be a wash,does it seem slightly rich?If anything your going to need to run them and read plugs and possibly go down slightly to compensate,Smitty

Lmarth

Stratman- To build on what Smitty said, you don't indicate what jetting's in there now. The Merc manual says both carbs have 78's in the Primaries and 88's in the Secondaries. 4.5 IN-HG power valve in the front for starters. I'm embarrassed to say that I run 800SC's in the Great Lakes and can't tell ya how they're jetted. I've got a 150 hours on a Sterling rebuild and haven't had to touch anything. Sorry I couldn't be more help.

stratman

Thanks for the replies fellas I haven't turned a screw on 'em yet so I have no clue what they're based at... This is my first supercharged set up and was curious if they ran a richer mixture to compensate for boost..

Lmarth

I think you're partially right based on the conversation I had with the folks at Sterling. They told me that Mercruiser purposely jetted that motor 'fat'. We can speculate why, but a little extra protection against bad gas, overheating,detonation,etc would make sense. Sterling shipped the motors with 15w-50 Mobil 1. They said to not run the oil more than 20 hours. I was told to check the level immediately after shutting down. Smell the dipstick for raw gas. If you smell gas or the oil level rises, then change oil/filter regardless of hours. Don't know if their thinking today has changed, but that's what they told me. I hope this helps...

articfriends

iTrader: (1)

In my experience with my blower motor is to truly be able to hold it at wot for sustained periods of time you want it rich to keep the a/f ratios down in the mid to lower 11's (11.6-11.2). A carb motor it is more of a compromise than a efi motor,you end up with it running a little rich when you don't need it to be so it doesn't melt down under sustained wot,so fuel dilution/contamination is something you have to keep a close watch on in your oil. My efi is even set rich,it could probably be leaner for short ,quick burst but thats no fun!If i had a pair of 800 sc's i would verify that the jets are at least as big as what came originally,run it and check the plug color,Smitty