Zinc Pencil Anode 3/4" NPT x 3/4" x 3-3/8" – CMT-E4
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Martyr CMT-E4 is a zinc pencil anode sized 3/4" NPT x 3/4" x 3-3/8", used to help protect marine engine cooling passages, heat exchangers, oil coolers, and other internal raw-water components from galvanic corrosion in saltwater service. This is a complete pencil anode with brass plug. Zinc is intended for saltwater use.
Key Features
- Zinc pencil anode with brass plug
- Thread size: 3/4" NPT
- Anode diameter: 3/4"
- Anode length: 3-3/8"
- Complete engine cooling system anode assembly
- Designed for internal corrosion protection in raw-water-cooled components
Engine Compatibility
This part is used across a range of marine engines, generators, and cooling-system components that take a 3/4" NPT pencil anode in the 3/4" x 3-3/8" size. Fitment should be confirmed by plug thread, anode diameter, anode length, and installed housing style rather than by engine family alone.
Serial Number Fitment Notice
Fitment should be confirmed by the installed anode dimensions and thread specification rather than serial number alone. Match the existing anode by 3/4" NPT plug thread, 3/4" anode diameter, and 3-3/8" anode length before ordering.
When This Part Needs Replacement
Replace when the zinc is heavily wasted, brittle, scaled, reduced in diameter, or no longer providing usable protective mass. Pencil anodes should be inspected regularly because they protect internal water-side components where corrosion can become expensive if service is delayed. This part is part of Martyr’s engine cooling system anode range.
Installation Notes
Install only where a 3/4" NPT pencil anode of this exact size is specified. Remove the old anode carefully, inspect the plug threads and sealing surfaces, and confirm the replacement length and diameter match the housing correctly. Zinc is the correct material for saltwater applications.
Alternate / Superseded Part Numbers
- CME4
- E-4
- CMT-E4
Parts Desk Insight
With pencil anodes, matching thread size alone is not enough. Diameter and length also need to match the housing so the anode protects properly without creating clearance issues inside the cooler or water passage. Martyr’s current CME listing shows CME4 as the 3/4" NPT model with a 3-3/8" length and 3/4" outside diameter.
Shipping
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.