This buyer’s guide highlights essential maintenance items for 115 HP four-stroke outboards. It covers oil change kits, oil filters, and water pump impeller replacements best suited for Mercury and Yamaha 4-stroke engines in the 75–115 HP range. The selections focus on reliability, compatibility, and on-water longevity. Ideal buyers include boat owners performing routine annual maintenance, a first-time outboard owner seeking complete kits, and preventive-care planners who want ready-to-use parts in one box. The following table summarizes the five recommended products to help you compare at a glance.
| Product | Brand | Best For | Why It Stands Out |
|---|---|---|---|
| Mercury 8M0107510 10W-30 Kit | MERCURY | Mercury 75–115hp EFI 2.1L | Comprehensive kit with oil, filter, drain hose, and corrosion inhibitors |
| Quicksilver 10W-30 4-Stroke Kit | Quicksilver | Mercury 70–115hp 2.1L | All-in-one kit with premium filter and oil, designed for long-term reliability |
| GHmarine 68VW0078 Water Pump Impeller Kit | GHmarine | Yamaha 75–115hp 4-stroke | Complete impeller kit with housing for Yamaha 4-stroke models |
| Mercury 8M0081917 25W-40 Kit | MERCURY | Mercury 75–115hp EFI 1.7L | Complete oil change kit with oil and essential components |
| UanofCn 68VW0078 Water Pump Kit | UANOFCN | Yamaha 50–115hp 4-stroke | Impe rler kit with housing for a wide Yamaha range |
Mercury 8M0107510 10W-30 4-Stroke Oil Change Kit
Best for Mercury 2.1L 75–115hp EFI FourStroke outboards (serial No. 2B094996 and up). This kit includes five 1-liter bottles of Mercury 10W-30 4-Stroke Marine Engine Oil, an oil filter, oil drain hose, and instructions. It also includes a marine-specific additive package with corrosion inhibitors to protect the engine on the water and in storage. Choose this if your engine is Mercury and around the 115hp mark for a complete service in one box.
Caution: Ensure your engine’s serial and model match the kit’s applicability to avoid mismatched oil specifications.
Quicksilver 10W-30 Oil Change Kit for 4-Stroke 75–115hp
Best for Mercury 70–115hp 2.1L outboards. This all-in-one box includes five 1L bottles of Quicksilver 10W-30 4-Stroke Marine Engine Oil, a premium Quicksilver oil filter, and a drain hose. It includes corrosion inhibitors for on-water protection and storage readiness. Opt for this kit if you want a Quicksilver-branded oil and filter with a focus on low wear and clean lubrication across the full 75–115 hp range.
Limitation: Designed for Mercury/Mercury-compatible outboards; verify compatibility with your exact serial range before purchase.
GHmarine 68VW0078 Water Pump Impeller Kit
Best for Yamaha Outboard 75–115 HP Four-Stroke. This water pump impeller repair kit with housing replaces Yamaha models including 68V-W0078-00-00 and Serra/Mallory equivalents. It helps restore cooling performance and prevent overheating. Choose this kit if you need a direct Yamaha-compatible impeller replacement with housing included.
Limitation: Verify that your Yamaha model uses the 68V-W0078 family to ensure fitment.
Mercury 8M0081917 25W-40 Oil Change Kit
Best for Mercury 1.7L 75–115hp EFI FourStroke engines (serial No. 1B366823-2B094995). The kit provides five 1L bottles of Mercury 25W-40 4-Stroke Oil, a filter, drain plug seal, and instructions. It features an oil additive package with corrosion inhibitors for water use and storage. Opt for this kit when you prefer Mercury’s own 25W-40 formulation for older or slightly different engine configurations within the same power band.
Limitation: Ensure your engine expects 25W-40 oil; some models may still require 10W-30 equivalents in specific conditions.
UanofCn 68VW0078 Water Pump Kit for Yamaha 4-Stroke
Best for Yamaha 50–115hp 4-Stroke Outboards. This water pump impeller kit with housing fits models including 68V-W0078-01-00 and 68V-W0078-00-00 and covers a broad Yamaha range. It’s a solid choice when replacing a failed impeller to maintain cooling efficiency and engine longevity. Choose this if you need a versatile Yamaha-compatible impeller kit with housing.
Caution: Confirm your Yamaha model’s exact water pump part number to avoid incompatibility with non-68V-W0078 variants.
Buying Guide
What maintenance items should you stock for a 115 HP four-stroke outboard?
- Oil change kits matched to your engine brand and displacement. Look for kits that include oil, filters, and connection hardware.
- Water pump and impeller replacements to prevent overheating. Ensure the kit includes a housing if required by your model.
- Corrosion inhibitors and storage additives when you plan to store your boat for extended periods.
How to choose between Mercury and Quicksilver oil kits?
- Brand alignment: Mercury kits are designed for Mercury engines, while Quicksilver is compatible with Mercury/Mercury-like systems and may be preferred for dealer compatibility.
- Oil viscosity: 10W-30 suits many 4-stroke Mercury engines; 25W-40 is an alternative for some older configurations. Confirm your manual’s specification.
Is a water pump kit the right choice?
- Yes, if your Yamaha or Mercury engine shows signs of cooling inefficiency or you’re performing preventive maintenance.
- Look for complete kits with impeller, housing, seals, and fasteners to ensure a proper rebuild.
FAQ
- What oil type should I use for a 115 HP four-stroke? Answer: Use the oil specified by your engine’s manual; common choices include 10W-30 for many 4-stroke Mercury engines in the 75–115hp range.
- Do these kits include filters? Answer: Yes, the Mercury and Quicksilver oil change kits typically include filters.
- Can I mix brands of oil and filter? Answer: It’s best to stay consistent with the engine manufacturer’s recommendations, but mixing is generally not recommended for best performance.
- When should I replace a water pump impeller? Answer: Replace if you notice overheating, reduced water flow, or if the service interval recommends it.
- Are these kits suitable for storage protection? Answer: Many kits include corrosion inhibitors to aid storage; follow the manual for proper storage practices.