Replacing your boat's inboard engine is a big decision, and in the marine engines propulsion category you typically face a trade-off between upfront cost and long-term capability. Two used engines frame that choice: a MerCruiser V8 with 433 hours and a Yanmar diesel that is shipped by sea. Their price gap is significant, so the right pick depends on your boat, your budget, and how much logistics you want to take on. Both are used, so your decision will also be shaped by the seller's description and what you're willing to inspect.
Quick Verdict
If you want the most boating for the least money, the MerCruiser Marine 5.7 L 350 V8 Blue Water Inboard Engine is the smart pick. It's a used V8 with 433 hours, and it's listed as drop-in ready. If you need a 200 HP diesel and are prepared for international shipping and extra port fees, the Yanmar 4LHA-STZP is worth the larger investment.
Price and Spec Comparison
| Attribute | MerCruiser 5.7L V8 | Yanmar 4LHA-STZP |
| Price | $4,500 | $15,000 |
| Condition | Used | Used |
| Engine | V8 inboard | Diesel inboard |
| Country of Origin | United States | Japan |
| Manufacturer Part Number | 350 | 4LHA-STZP |
Where Each Product Wins
MerCruiser Wins for Budget Value
The MerCruiser is the cheaper engine by a wide margin, and that price gap is the single biggest reason to choose it. For a planing hull or a repower where cost matters most, this V8 offers a familiar platform from a U.S. manufacturer. The used condition means you should inspect it thoroughly, but the lower price gives you room in the budget for that work. The part number 350 makes it easy to match against your existing MerCruiser setup.
Yanmar Wins for Diesel Power
The Yanmar is a 4-stroke diesel, and if your boat is configured for diesel, this is the clear match. It's listed as tested and made in Japan. The higher price is a real consideration, but it brings a diesel engine that could be the right choice for a cruising boat that needs torque and range. The part number 4LHA-STZP is a specific Yanmar model, so you can verify it fits your boat before committing.
Product Notes
MerCruiser Marine 5.7 L 350 V8 Blue Water Inboard Engine 433 HRS Drop In Ready
At $4,500, this used V8 is the value pick in this comparison. It has 433 hours on it, so plan to have a mechanic give it a once-over before you rely on it. It's described as drop-in ready, which can ease a replacement project. If you're keeping a MerCruiser-powered boat alive or repowering on a modest budget, this engine gets you on the water without a huge outlay. The main limitation is that it's used with substantial runtime, so set aside money for possible maintenance.
Yanmar 4LHA-STZP inboard marine diesel engine tested ok - Ship by sea
The $15,000 price reflects a 200 HP 4-stroke diesel from Japan, and it's listed as tested and in working order. This engine is shipped by ocean freight from India, so expect a 30-60 day transit time, mandatory ISF filing for U.S. ports, and local port charges that fall on you. It comes with no warranty, so the testing claim is your main assurance. If your boat needs diesel power and you're comfortable with international shipping paperwork, this Yanmar is the more capable engine-just be ready for the logistics.
Final Choice by Use Case
- Budget-conscious repower: Go with the MerCruiser 5.7L V8. It offers an affordable path to a proven V8 form factor.
- Long-range diesel cruiser: Choose the Yanmar 4LHA-STZP. The tested diesel and Japan build make it worth the extra cost if your boat is set up for diesel and you can handle the shipping steps.
