The original heat exchanger used on the M-25 was a small 2" X 16" cylinder. When pushed hard, motoring near hull speed for 20 or 30 minutes, or attempting to claw off of a lee shore in rough conditions for example, the the M-25 would overheat.
There were two iterations of the 3" diameter heat exchanger for the M-25XP, this is the first that used a single bracket to mount with clamps. The bracket is no longer available, but can be reused if yours is in good shape, or purchase our replacement bracket set #Z4365.
This first iteration of the replacement 3" diameter heat exchanger is a direct replacement for the original part used on the M-25XP and is an excellent retrofit upgrade for the M-25 engines as well. This heat exchanger was then replaced by our #Z3462 with slightly different port locations. This is not a direct replacement for the later B series M-25XPB and M-35B engines which uses a different model yet.
This entire assembly contains NO ferrous metal. It is about 10 pounds of bronze and copper and is hand made right here in the United States!
• Raw water hose sizes: 5/8"
• Engine water hose sizes: 7/8"
• Diameter of heat exchanger body: 3"
• Length of heat exchanger body: 13"
• Zinc: 3/8" thread, 11/16" wrench
1) This item does not conform to the shipping table in the Shopping Cart. Additional shipping must be calculated. When you place your order we always call with a shipping quote before billing your card. For a quote in advance, just call 800/959-7245.
2) The original 2" X 16" used brazed on brackets on the M-25 and M-25XP. This intermediate replacement 3" X 13" used a single bracket and clamps to secure the heat exchanger. The bracket is no longer available so use your original if still in good shape or purchase our replacement bracket set #Z4365.
3) Uses our replacement zinc Z2552 shown below under "May We Also Suggest".
4) Some of the early M-25s had a bracket that was fastened to the top of the bell housing and was mounted horizontally. If that is the configuration on your engine, you will need to use a 3" diameter pipe to flatten out the existing bracket to accommodate this larger diameter heat exchanger and reuse the original bracket.