Crankshaft 1 (66T-11412-00) – Fits Yamaha 40HP 2-Stroke Outboard Motors
Crankshaft 1 (66T-11412-00) – Fits Yamaha 40HP 2-Stroke Outboard Motors is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Product Details
This is a replacement Crankshaft 1 (66T-11412-00) designed to fit Yamaha 40HP (40X, E40X) 2-Stroke outboard motors manufactured between 1998 and 2017. As an essential internal engine part, this component is one of several that form the complete crankshaft assembly, responsible for converting piston motion into rotational force.
This part is a direct replacement for Yamaha OEM part numbers 66T-11412-00, 66T-11412, and 66T1141200.
- Designed for direct OEM-equivalent installation.
- Specifically for 2-stroke gasoline outboard engines.
- Engineered as a component piece for the crankshaft assembly.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 66T-11412-00 |
| Yamaha | 66T-11412 |
| Yamaha | 66T1141200 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This component is specifically designed for select 2-stroke Yamaha outboard models. Verify your engine's model code and year of manufacture before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 40X M(W/T)HS/L | 40 | 2-Stroke | 1998–2000 | 66T-11412-00 | |
| Yamaha | 40X M(W/T)HS/L | 40 | 2-Stroke | 2010–2013 | 66T-11412-00 | |
| Yamaha | E40X M(W/T)HS/L | 40 | 2-Stroke | 1998–1999 | 66T-11412-00 | |
| Yamaha | E40X M(W/T)HS/L | 40 | 2-Stroke | 2001–2004 | 66T-11412-00 | |
| Yamaha | E40X M(W/T)HS/L | 40 | 2-Stroke | 2006–2008 | 66T-11412-00 | |
| Yamaha | E40X MHL | 40 | 2-Stroke | 2010–2017 | 66T-11412-00 | |
| Yamaha | E40X MHS | 40 | 2-Stroke | 2010 | 66T-11412-00 |
Technical Specs
- Product Type
- Crankshaft Component (Crank 1)
- Installation
- Direct OEM replacement
- Fuel Type
- Gasoline
- Application
- For 2-stroke outboard engines
- Dimensions
- 15.5" L x 11.5" W x 12.0" H
What’s in the Box
- 1 x Crank For YAMAHA Outboard (66T-11412-00 / 66T-11412 / 66T1141200)
Installation Notes
- Disconnect the battery and all fuel lines to ensure safety. Drain engine oil completely.
- Remove the engine cover and proceed to detach the powerhead from the midsection.
- Systematically disassemble the engine block to gain access to the internal crankshaft assembly.
- Carefully extract the old "Crank 1" component, noting its orientation and connection points.
- Inspect adjacent bearings, seals, and connecting rods for wear or damage and replace if necessary.
- Install the new crankshaft component, ensuring it is correctly aligned with other assembly parts.
- Reassemble the engine block according to the manufacturer’s service manual, paying close attention to torque specifications for all bolts.
- Reinstall the powerhead, reconnect fuel lines, and refill with the correct grade of oil.
- Before returning to water, test the engine at low RPMs to confirm smooth operation.
Troubleshooting & FAQ
How do I confirm this fits my specific Yamaha 40HP model?
The most reliable method is to match your engine's model code and year to our compatibility table. You can find this information on the identification plate on your outboard's mounting bracket. Also, visually compare the part to your original before installing.
What are the signs of a failing crankshaft component?
Common symptoms include excessive engine vibration, a knocking or ticking sound from the engine block, loss of power, or difficulty starting. In severe cases, the engine may seize. These signs warrant an immediate inspection by a qualified mechanic.
Is this the complete crankshaft assembly?
No. This part, referred to as "Crank 1," is a single component of the complete crankshaft assembly. The full assembly consists of several interconnected parts. This listing is only for the specific component pictured and numbered.
What is the typical replacement interval for a crankshaft?
Crankshafts are not typically a routine maintenance item and are designed to last the life of the engine. Replacement is usually only necessary due to catastrophic failure, damage from a thrown connecting rod, or excessive wear on bearing journals.
Does this part require special tools for installation?
Yes, replacing a crankshaft component is a complex task that requires specialized tools, including a flywheel puller, torque wrench, and potentially bearing presses. Professional installation is highly recommended due to the precision required.
What is the difference between an OEM and an aftermarket part?
This listing is an aftermarket replacement (not OEM). It's built to OEM-level specifications with comparable materials and manufactured in an ISO 9001 certified facility, with batch inspections for quality and consistency.
How fast is shipping?
We ship worldwide, with typical transit times of 5–15 days for most regions. Standard shipping is free. If available for your location, expedited shipping options will appear at checkout.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. Should an issue arise, contact our support team with your order details. Returns of unused items in their original condition are accepted within our standard return window. Please see our full policy page or contact us for instructions.
Safety & Important Info
- Verify images and specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is strongly recommended for safety, performance, and to prevent engine damage.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with an average transit time of 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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