Engine
Engine 9HP — Yanmar 1GM10 wiring diagram
Yanmar 1GM10 single-cylinder marine diesel with 1.0 kW starter. The 2017 manual lists a 35 A alternator; current product data lists 40 A. Modeled 150 A cranking and 250 A surge are estimates, with actual alternator output dependent on generation.
- Continuous draw
- 150 A
- Rated output
- 40 A
- Surge current
- 250 A
Wiring diagram
How the 1GM10 9HP is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 120 mm² · 4/0 AWG
- Example fuse
- 250 A
- Cranking current
- 150 A
- Voltage drop
- 1.1%
Sized against ABYC E-11. The cranking current is what the starter draws. ABYC E-11 doesn't require a fuse on a cranking-motor conductor, so the fuse shown is the usual cranking-rated (Class T) choice, sized to hold the crank without nuisance tripping — it isn't there to protect the wire. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
Supporting parts
- 6.1 m total of 120 mm² (4/0 AWG) marine cable
- Terminations for 120 mm² cable, matched to the equipment's screw terminals, leads or studs
- 250 A cranking-rated (Class T) fuse at the battery
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. 0AGMM-EN0012 \u2014 third edition, January 2017), checked 2026-10-01. Manufacturer documentation →
Engine and edition
The GM operation manual identifies the shaft-drive 1GM10 separately from 1GM10C saildrive and 1GM10V V-drive versions. It specifies a 12 V, 1.0 kW starting motor and 35 A alternator for this edition. Current Yanmar product information lists 40 A: the catalog 40 A represents that later offering, not every installed GM engine.
What the terminals mean
`Starter` represents the high-current starter supply, `Alt B+` the alternator charging output, and `Block GND` the intended negative return on an earth-return installation. They are functional drawing ports, not three interchangeable physical studs. Trace any factory link between alternator B+ and the starter battery stud before changing it; do not duplicate or remove that link without accounting for the original harness.
Controls and protection
Use the drawing for the fitted panel. The manual provides separate panel/harness arrangements, including a 30 A engine-harness fuse and a 3 A instrument fuse on the corresponding panel drawing. These protect control wiring, not the full starter cable. Check charge, oil-pressure and temperature indications before departure. Stop the engine with its stop control; disconnecting the battery is not the stop procedure.
Checks and model limits
Limit an electric starting attempt to 15 seconds and allow the starter to recover between attempts. The catalog 150 A draw and 250 A surge are estimates, not values established by dividing starter output power by battery voltage. Test the installed starter and battery under load. The drawing omits the panel, fuse holders, stop cable, alternator excitation wiring and any house-bank charging interface.
Source: manufacturer document — starting printed pp. 39–41 (PDF 45–47), shaft-drive specifications p. 74 (PDF 80), electrical drawings pp. 81–83 (PDF 87–89). Legacy copies hosted outside the manufacturer site are manufacturer-authored archive documents; the review date does not make them current installation instructions.
Fit check
Connect it to the rest of your system.
Describe your setup to draft a system with 1GM10 connected. Review the selected parts and cable lengths, then edit the diagram in Crimp.
The model only picks parts and draws the connections. Every wire size and fuse rating still comes from Crimp's own sizing, never from the model.
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Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
Yanmar 1GM10 single-cylinder marine diesel with 1.0 kW starter. The 2017 manual lists a 35 A alternator; current product data lists 40 A. Modeled 150 A cranking and 250 A surge are estimates, with actual alternator output dependent on generation.
- Continuous draw
- 150 A
- Rated output
- 40 A
- Surge current
- 250 A
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
Starter
positive · input
Alt B+
positive · output
Block GND
ground · bidi
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
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Plan your installation with 1GM10 9HP.
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