I was wondering what the initial timing is for a 94' 502 EFI, is it 8* BTDC? Also what is the general consensus regarding bumping it up a couple of degrees to 10, and if I did would I need to run 89 or 93 octane, or stick with the 87? Thanks!

ITS WORTH LESS THAN 5HP, NOT WORTH THE DIFFERENCE IN FUEL COST.

well if you install one of the EFI upgrade kits, one of the steps is to bump it up to 10 degrees, from the factory 8 degrees, I would run 89 octane just to be safe, anytime you add more HP it will cost you more fuel, formula more air plus more fuel equal more horsepower, at least most of the time

REMEMBER, WHEN YOU SET THE TIMING YOU HAVE TO PUT THE ENGINE (ECU) IN BASE TIMING MODE. 8* INITIAL IS CORRECT. THE ONLY WAY TO TELL IF MORE TIMING WOULD BE BENEFICIAL IS TO SEE IF THE COMPUTOR PICKS UP KNOCK WITH THE TIMING ADVANCED TO W.O.T. YOU WOULD HAVE NO WAY OF KNOWING WITH OUT USING A LAPTOP OR SCAN TOOL. IF ENGINE KNOCK IS DETECTED, THE ECU WOULD TAKE OUT THE REQUIRED AMOUNT OF TIMING TO REDUCE THE KNOCK, AND YOUR TIMING CHANGE WOULD NOT MAKE ANY DIFFERENCE ANYWAY. IT IS NOT GOOD TO OPERATE THE ENGINE FOR ANY EXTENDED TIME WITH THE COMP. HAVING TO TAKE OUT KNOCK. HOPE THIS HELPS........
STEVE

Thanks for the help guys, any idea where I can get the tool to set the timing?

The Mercury part # for the tool is 91-805747A 2. You can get it from your dealer or order it from www.boatfix.com (click on the Mercury parts banner on the left of the screen). It costs about $10.

OR

You can just use a paper clip. Remove the protective cover from the DLC connector and connect the black and white wires with the paper clip.

Great! Thanks for the info Ric!

ttt

The Merc Service manual says you need a scan tool and timing light to set timing. With the scan tool priced around a grand I don't think I will be getting one soon. Can you still set the timing, without the scan tool and still get the computer into the "Service Mode" ? Does using the paper clip method Ric232 sugested get the computer into the "Service Mode"? Also what is the general consensus on bumping up the timing on a stock 502 Mpi. a couple of degrees? I tend to run wide open for long periods.

scarab22, read Ric232 post again, but the clip works also.
QUOTE
The Mercury part # for the tool is 91-805747A 2. You can get it from your dealer or order it from www.boatfix.com (click on the Mercury parts banner on the left of the screen). It costs about $10.