Mercury 25MH 25HP Outboard – 15in Shaft, Tiller, Manual Start, EFI
For open water, Mercury 25MH pushes 25 horsepower. Tiller steering runs through a 15-inch shaft. EFI backs up the rated output. Boaters pick it for a straightforward, low-maintenance setup.
- 25 horsepower, ready to run
- Fits 15-inch transom height
- Tiller steering, simple setup
- Manual start, no battery needed
- EFI fuel delivery system
Description
Deploy the battery-free, 500cc Mercury 25MH to bypass dead marine battery failures on remote hunting trips. The internal magnetic EFI system fires the inline-three block using one manual recoil pull. You navigate backcountry duck blinds without relying on complex electrical wiring. A quick tape measure check validates this lightweight manual start mercury outboard fits standard hulls perfectly.
Tired of dragging heavy lower units across shallow gravel banks? The manual tilt bracket acts as a simple physical fix. You grab the rear cowl grip and lock the gearcase up high. Engineers coat all external alloy surfaces with multi-layer marine primer. This physical barrier blocks surface rust when dragging jon boats onto rocky shorelines.
Key Features of Mercury 25MH
- Battery-Free EFI: Atomizes fuel instantly using internal magnetic power, drastically reducing physical pull-start effort even in freezing duck hunting weather.
- 15-Inch Standard Shaft: Eliminates lower unit drag on flat bottom jon boats, increasing top speed and fuel efficiency on light hulls.
- Manual Tilt Bracket: Features a rigid mechanical lock, safely holding the 60 kg gearcase up high when dragging the hull over gravel banks.
- Adjustable Tiller Friction: Lets the operator set desired steering stiffness physically, reducing arm fatigue during long winding river runs.
- Manual Recoil Starting: Strips heavy starter motors and battery cables from your boat layout, maximizing available gear payload capacity.
- Multi-Layer Marine Primer: Coats all external alloy surfaces tightly, blocking surface rust across years of hard use in harsh backcountry environments.
- Through-Prop Exhaust: Minimizes atmospheric noise drastically, crucial for sneaking up on hunting locations without spooking sensitive wildlife.
- Manual Trim Pin Holes: Allow mechanical adjustments to the running attitude, optimizing hull draft based on shifting passenger weight distribution.
- Accessible Inline Fuel Filter: Traps dirty gas debris before it reaches the fuel injectors, preventing sudden engine stalling miles from the ramp.
- Balanced Carrying Handle: Integrates cleanly into the cowl base, providing a secure physical grip when lifting the engine onto the transom.
Why Choose Mercury 25MH
You buy this motor to keep rigging dead simple on a standard 15-inch transom boat. It offers zero remote steering capability and lacks heavy power trim cylinders. Do not attempt to mount this short shaft on a 20-inch tall transom. Finding a reliable manual recoil start outboard solves heavy payload limits.
- Weigh your boat to verify it safely handles this specific 60 kg engine block mass.
- Check the tiller handle sweep path to confirm it clears your rear seating bench.
- Keep local lakes clean by running highly regulated four-stroke engine configurations.
Ideal Application and Vessel Fitment
This 15-inch manual-start tiller engine is engineered for standard-transom aluminum jon boats, heavy-duty inflatable tenders, and minimalist fiberglass marsh skiffs where saving weight is critical. By stripping away heavy electric starter motors and 12-volt battery banks, operators gain maximum payload capacity for hunting gear and fishing tackle. The advanced battery-free EFI guarantees this mercury short shaft tiller outboard fires instantly in freezing weather, making it the ultimate off-grid power plant for rugged backcountry exploration far beyond cell service.
Warranty, Support and Maintenance
Authorized recreational operation receives a 3-Year Limited Warranty alongside a 3-Year Corrosion Warranty. Registered commercial applications fall under a strict 1-Year Limited Warranty with zero corrosion coverage applied to the block. Scheduled maintenance requires replacing gearcase lubricants and changing oil filters at manual-specified intervals. Always save all physical service records. Your engine serial number acts as the only way to source exact genuine replacement parts. Mulmotor provides product-information support before purchase and assistance with order-related questions.
Mercury 25HP 25MH EFI Specs
| Brand | Mercury Marine |
| Full Model Code | 25MH EFI |
| Country of Origin | USA / Japan Componentry |
| Engine Family/Series | FourStroke Portable |
| Engine Type | Inline 3 / SOHC / 4-Stroke |
| Displacement | 0.50 Liters (500 cc) |
| Horsepower | 25 HP @ 5800 RPM |
| Full Throttle RPM Range | 5400 - 6000 RPM |
| Fuel Induction System | Electronic Fuel Injection (EFI) |
| Alternator Output | 15 Amps |
| Gear Ratio | 2.17:1 |
| Shaft Length | 15" (Short) |
| Dry Weight | 60 kg (132 lbs) |
| Bore x Stroke | 61 x 57 mm |
| Starting & Steering System | Manual Start w/ Tiller Handle |
| Trim/Tilt Method | Manual Tilt |
| Oil Capacity | 1.8L |
| Recommended Fuel | 87 Octane |
| Standard Warranty | 3-Year Limited Pleasure |
| Application | Simplistic, battery-free EFI operation for rugged utility and fishing skiffs. |













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