Maybe this will help everyone with questions regarding 3 liter Mercury's:
Oil:
-These are the "top recommendations". Refer to your owner's manual for other oil specifications!
-ALL EFI/CARB 3.0L Engines: Mercury or Quicksilver Premium PLUS
-All STANDARD Optimax (75-250): Mercury or Quicksilver DFI/Optimax Oil
-ALL ProXS Models: Optimax/DFI Oil. Mercury or Quicksilver Premium PLUS is acceptable, but Optimax/DFI oil is RECOMMENDED due to a better additive package to help combat carbon deposits.
-ALL Racing/XS Models: PREMIUM PLUS

- (Note..... there was some conflicting information on Merc's Website- follow this recommendation for the latest information as it's released!)

Battery:
-MINIMUM 800CCA or 1000 MCA Capacity. More is better! Use Stainless Steel Lock nuts (don't use wing-nuts).
-IF you have a lot of accessories you are running, KEEP IN MIND that this specification is for the ENGINE CRANKING BATTERY. You may need to INCREASE the battery specification to provide adequate cranking capacity based on your accessories being run!
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(Recommended Batteries after Testing and information courtesy of Mercury Marine Research & Development)

-Odyssey PC1500, PC1700, PC2150 and PC2250.
-Optima Group 31
-West Marine Sea Volt Group 27 AGM.
-Cabela's Advanced Angler ** Group 24 and 27.
-Trolling Thunder TT1175 and TT1370.
-Excide Megacycle (Mercury Brand) MC-31 and XMC-31.
-Sears Die Hard Platinum 34M and 31M.
-Deka Sea Mate 8A27M and 8A31DTM.

** During initial testing, these batteries do not meet their advertised cranking ratings.
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Spark Plugs:
-QL77CC (Champion) for 3 Liter EFI's (.035" 2001 and prior and ALL 250XB, .040" 2002-up)
-IZFR5G@ .032-.033" for Standard Opti's 135-225HP and 200 ProXS PRIOR TO Serial Number#1B912786
-IZFR5J @.032-.033 for 75-115 Opti's
-IZFR6J for 150, 175, 200 ProXS (Serial #1B912786-up) & 225-250 ProXS and Racing XS Motors
-2005 & prior: .032-.033"
-2006 & up: .042-.044" gap for best idle performance. (150/175/225/250 ProXS/XS)
- 250 XS/ProXS can use IZFR6J (gapped to .042-.044") OR IZFR6J-11 (pre-gapped, currently a "factory only" plug)
-2006 & up 225 ProXS: .042-.044"
-175 ProXS: .042-.044"
*** 200 ProXS Models manufactured PRIOR TO 2/1/12 utilize IZFR5G Plugs.
*** 200 ProXS Models manufactured AFTER 2/1/12 (Serial Number 1B912786 and later) will utilize IZFR6J (gapped at .042-.044") due to production changes in the engines.

-IZFR7M for 300XS: .044" Gap


FUEL:
-All models- MAXIMUM ETHANOL CONTENT: 10%. Ethanol content may adversly affect engine performance.
-See "Mercury's View of Ethanol" on Sherm's board at: Mercurys take on Ethanol blended fuel
-Standard Opti's (ALL) 87 Octane MINIMUM.
-XS, XB or Racing PRIOR to 2006- CONSULT OWNER'S MANUAL! Most require High-Test!
-ProXS and 250XS 2006-later: 87 Octane MINIMUM. Idle quality may improve with 89 Octane (mid-grade).
-300XS- Consult Owner's Manual. High Grade (minimum 91 Octane) fuel required!

Fuel Additive Recommendations:
-Stabilize fuel ANYTIME fuel will not be consumed and replaced within 15 days!!!
-Optis (ALL, including XS & ProXS): Quickleen in EVERY TANK OF FUEL. You CAN combine Mercury QuickCare or QuickStor Fuel System Treatment & Stabilizer (or Sea-Foam if you prefer it) with Quickleen. Use the recommended "dose" of each product per the bottle instructions. For anyone questioning Quickleen recommendation- see Service Bulletin 2001-12 (yes, it's been recommended since 2001!!!).
-Quickleen may be used in ANY Mercury engine- it helps to prevent/remove carbon buildup (primary purpose).

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"Mercury Component Cocktail" (Chemically, this works much the same as the below mentioned cocktail, and requires less components.)

-1oz Mercury QuickCare per 5 gallons fuel
-1oz Mercury QuickLeen per 5 gallons fuel
(If leaving fuel in boat for more than 30 days, be sure to also add Mercury QuickStor).
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"Alternate Cocktail" (IMO, this combination results in clean injectors, direct injectors and spark plugs):

-1oz Marine Stabil or Mercury QuickCare per 6 gallons fuel
-1oz Quickleen per 6 gallons fuel
-1-2oz SeaFoam per 6 gallons fuel


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Fuel/Air Pressures (Optimax):
Two different pressure differentials are used:
-75-115 3 cyl. and ALL XS Racing & 225-250 ProXS Motors (And the 250 Optimax) use 94/108 Air/Fuel Pressures (Fuel pressure equals air pressure + 15psi)
-All other "standard" Opti's use 80/90 Air/Fuel Pressures (Fuel pressure equals air pressure + 10psi)
-IF YOU HAVE NO AIR PRESSURE- YOU HAVE LITTLE OR NO FUEL PRESSURE. The fuel pressure is DIRECTLY relative to the AIR PRESSURE! So- if you have low or no fuel pressure, CHECK the air pressure, and check for AIR LEAKS before you start replacing fuel pumps!


*** Neat little "rule of thumb": If it has "gray" Direct injectors, Air/Fuel is 94/108 and it uses a spark plug that 'ends in J or M' *** (one motor exception- it had black injectors with a "white dot"- consider those to be "gray").

If the direct injectors are Black, Black with a Blue Dot, or Blue, the Air/Fuel is 80/90 and the spark plug probably ends with a "G".

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Good info Danny sure that will help the mercury guys out

ttt

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